Tackling social disconnection: An umbrella review of RCT-based interventions targeting social isolation and loneliness

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Nilsen, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-3351098/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background Social isolation and loneliness are urgent public health concerns associated with negative physical and mental health outcomes. Understanding effective remedies is crucial in addressing these problems. Objectives To synthesize and critically appraise scientific evidence on the effectiveness of social isolation and loneliness interventions overall and across subgroups. We focused on systematic reviews (SRs) of randomized controlled trials (RCTs). Methods We searched seven databases (June 2022 and updated June 2023) and supplemented the search with grey literature and reference screening to identify SRs published since 2017. Screening, data extraction, and quality assessment using the AMSTAR2 tool were conducted independently by author pairs, with disagreements resolved through discussion. Findings: We included 29 SRs, 16 with meta-analysis and 13 with narrative synthesis. All SRs focused on loneliness, with 12 additionally examining social isolation. Four SRs focused on young people, 11 on all ages, and 14 on older adults. The most frequently examined intervention types were social (social contact, social support), psychological (therapy, psychoeducation, social skills training), and digital (e.g., computer use and online support). Meta-analyses indicated small-to-moderate beneficial effects, while narrative synthesis demonstrated mixed or no effect. Social interventions for social isolation and psychological interventions for loneliness were the most promising. However, caution is warranted due to the effects’ small magnitude, significant heterogeneity, and the variable quality of SRs. Digital and other interventions showed mixed or no effect; however, caution is advised in interpreting these results due to the highly diverse nature of the interventions studied. Conclusion This overview of SRs shows small to moderate effectiveness of social interventions in reducing social isolation and psychological ones in tackling loneliness. Further rigorously conducted RCTs and SRs are needed to guide policy decisions regarding the implementation of efficacious and scalable interventions. Evaluation should focus on both preventive structural interventions and tailored mitigating strategies that address specific types and causes of loneliness. Psychology Figures Figure 1 Figure 2 Introduction Social isolation and loneliness (SIL) are pervasive and serious public health concerns associated with numerous detrimental physical and mental health outcomes, including mortality [ 1 – 4 ]. Associations also extend to adverse impacts on prosocial behavior (e.g., volunteering), social participation, healthcare utilization, productivity, and daily functioning [ 5 , 6 ]. Thus, SIL generates a wide array of harmful and debilitating effects, ranging from individual suffering to broader societal burdens and financial costs. Social isolation and loneliness, although conceptually similar, are distinct and moderately correlated phenomena [ 7 ]. Social isolation (“being alone”) refers to an objective state characterized by limited social contacts and infrequent meaningful contact with others [ 8 – 10 ]. In contrast, loneliness (“feeling alone”) is a subjective experience and refers to the negative feeling caused by a discrepancy between actual and desired social connection and social contact [ 5 , 11 , 12 ]. The prevalence of social isolation varies across its specific indicators, but generally increases in later life [ 13 ]. For instance, over one-third of adults aged 65 and above, and more than half of those aged over 80, live alone in Norway and several other Western countries [ 13 , 14 ]. Loneliness is also a widespread issue in Western countries, with approximately one-quarter of the adult population reporting that they “sometimes” or “often” feel lonely [ 15 , 16 ]. The proportion is even higher among the youngest and oldest age groups and a significant increase among adolescents and young adults has been documented in many Western countries over recent decades [ 17 , 18 ]. Among older age groups, the rates appear relatively stable, yet the absolute rates will in many countries likely rise in the future due to the aging of the population [ 19 , 20 ]. Strategies are sought globally to prevent and alleviate SIL [ 21 ]. To this end, access to high-quality research evaluating intervention effectiveness is crucial. Although the development and evaluation of SIL interventions are still in their infancy compared to interventions for mental and physical health problems [ 22 ], the evidence base is rapidly expanding, accompanied by an increasing number of published systematic reviews (SRs). However, the quality and scope of SRs often vary, in terms of the focal intervention type, populations, delivery format, or outcome, making it challenging to obtain a comprehensive overview of an intervention’s effectiveness [ 23 , 24 ]. To address this limitation, systematic reviews of systematic reviews (termed umbrella reviews (URs)) can be conducted. URs systematically assess, and synthesize evidence from multiple SRs [ 25 ], to offer a comprehensive examination of the available information, allowing for a more robust evaluation of intervention effectiveness [ 23 ]. We identified six URs of interventions for reducing SIL [ 26 – 31 ]. These have conflicting findings, making it challenging to draw firm conclusions. Two suggest that interventions have small but significant effects [ 30 ], or that specific interventions such as mindfulness, social cognitive training, and social support are effective while others, such as befriending, technological interventions, and social training interventions, are not [ 31 ]. The other four URs conclude that interventions generally show no effect [ 28 , 29 ] or, based on digital interventions, show weak and inconsistent effects [ 26 , 27 ]. Factors contributing to these diverse findings include different study designs (randomized controlled trials (RCTs) and non-RCTs) and varying quality of evidence and reviews. Half of the URs are not published in peer-reviewed journals. Additionally, the pooling of analyses involving widely different types of interventions and populations further contributes to the challenges in synthesizing the evidence (see Appendix 1 for a detailed description of prior and current umbrella reviews). Furthermore, these URs reveal several knowledge gaps. Limited research has been conducted on adolescents and younger adults, despite the increasing prevalence of loneliness among these age groups. Only half of the URs also addressed social isolation, which has health impacts similar to loneliness [ 8 ]. The evidence also remains scarce for specific types of interventions. For example, the UR supporting the benefits of mindfulness is based on only two RCTs [ 31 ]. Non-RCTs and single group (pre-post) designs raise concerns related to internal validity and have been shown to significantly overestimate effect sizes compared to RCTs [ 32 – 35 ]. Synthesizing RCT-based evidence is necessary to provide a more reliable and accurate evaluation of intervention efficacy [ 32 ]. Encouragingly, the number of RCT-evaluated interventions has increased in recent years, and the quality of RCTs appears to be improving [ 7 , 36 ]. This highlights the need for a further UR to update the evidence and address these limitations. The aim of this UR is to synthesize and critically appraise scientific evidence on the effectiveness of SIL interventions. This UR includes all types of preventive and mitigating interventions for individuals of all ages, including children and youth. It adds to the existing UR literature by (i) only including SRs of RCTs, (ii) including only the most recent SRs (2017–2023), (iii) considering both published and non-published (grey) literature, (iv) analyzing overall and subgroup effects by intervention type), and (v) assessing both social isolation and loneliness. Our goal is to provide updated and valuable insights for researchers, policymakers, and practitioners in this field. Methods This UR was registered with PROSPERO (CRD42022329192) and is reported according to the Preferred Reporting Items for Overview of Reviews (PRIOR) reporting guideline (see Appendix 2) [ 25 ]. One deviation from the protocol involved excluding an eligible SR [ 37 ] since it included only one relevant RCT, which had already been included in three other included SRs. Inclusions and exclusion criteria Eligible SRs were written in English or Scandinavian languages and published in 2017 or later. SRs were required to have a clear PICO , a search of two or more databases, and an assessment of risk of bias. Eligible SRs needed to include data from RCTs and provide intervention data (e.g., effect size), with data provided separately for RCTs if non-RCT data were also included. Reviews of any population and any non-pharmacological types of preventive/mitigating intervention (e.g., befriending, social support, psychological interventions) were eligible. Any comparison treatment was acceptable (e.g., treatment-as-usual, other treatment, no care). Reviews including measures of the following outcomes were eligible: loneliness and/or social isolation (or close proxy measures, e.g., social contact). We excluded SRs that did not focus on social isolation or loneliness, SRs that did not measure or report effects comparatively, and SRs using other designs (e.g., scoping reviews). Search methods An information specialist (RAT) conducted a systematic literature search based on a search strategy that combined text words and controlled vocabulary (e.g., MEDLINE Medical Subject Headings), applying a method filter for SRs (see full search strategy in Appendix 3). The strategy was peer-reviewed by a second information specialist. The strategy was adapted for the following databases: MEDLINE (OVID), Embase (OVID), APA PsycINFO (OVID), Sociological Abstracts (ProQuest), CINAHL (EBSCO), Web of Science Core Collection databases (SCI-EXPANDED, SSCI, A&HCI, and ESCI), and Epistemonikos. The search was performed on June 16–17, 2022, and updated on 19 June, 2023. Grey literature was identified through searches in Google Scholar, Swemed+, Prospero, Open Grey System for Information on Grey Literature in Europe, OAIster, and The Campbell Collaboration on June, 20–21, 2022 (updated 22 June 2023). We also contacted researchers with relevant expertise for suggestions of SRs and searched reference lists of included SRs and prior URs (see Appendix 3). Screening and selection of reviews Search results were imported into EndNote [ 38 ], where records were de-duplicated. The results were loaded into Covidence [ 39 ] for screening. Titles, abstracts, and full-text articles were screened by two review authors independently, with disagreements resolved through discussion. Reasons for excluding full-text SRs were recorded (Appendix 4). When protocols for SRs were identified, up to three emails were sent to the authors requesting copies of the completed SRs. In the absence of a response, the study was excluded from the UR (see Appendix 5). Data extraction and quality assessment Pairs of authors conducted data extraction and quality assessment independently, with disagreements resolved through discussion. An Excel data extraction form was developed and piloted for this project . For each SR, data on the research question (aim), search strategy (number of databases, grey literature (no/yes), years covered), population, RCT characteristics (number, origin, sample size, sample characteristics (mean age, mental disorder, institutionalized vs. community dwelling, etc. ), outcomes and outcome measures, and review characteristics (Cochrane review (no/yes), GRADE assessment (no/yes), risk of bias/quality assessment measure), and results were extracted. We extracted data on intervention characteristics and findings, grouped, if possible, by type of intervention. This included the type of intervention (see below), nature of the intervention (procedure used), delivery format (group vs. individual), comparator(s), mode of delivery (face-to-face, internet, etc.), intervention provider (e.g., therapist, health worker), setting (e.g., long-term care), frequency and duration of intervention, follow-up details, author/year of included primary studies, and findings (e.g., overall and subgroup effects). Inspired by previous categorizations [ 33 , 40 , 41 ], interventions were pre-classified into 11 groups in the data extraction sheet (Table 1 ). Table 1 Intervention categories (used in the data extraction form) Social network and contact Promoting social contact and activity, expanding network size, providing opportunities for social interaction (e.g., online or group-based meeting or activities, video-calls with family, friendship clubs, shared interest groups, day care centers). Social support Providing social support through regular contact, care, or companionship (e.g., befriending) typically conducted by a volunteer or peer mentor. Unlike ‘social network and contact’, which focuses on reciprocity and mutual benefit, this category is more one-directional. Psychological/therapy Addressing social cognition or providing psychological support to cope with distress (e.g., psychotherapy, cognitive-behavioral therapy, mindfulness). The goal is to tackle negative thoughts and beliefs, influence social behavior and self-efficacy, and reduce barriers to socialization and secure social connections. Usually delivered by a trained therapist or health professional. Psychoeducation Education about topics related to loneliness, health, and well-being more broadly. Social skills training Educational interventions focused on improving friendship, communication, and interpersonal skills. Computer/internet Training in the use of information and communication technology, such as internet, email, and social media platforms. Digital Digitally delivered (e.g., video-conferencing, online support groups). Applied only when used by the systematic reviews and when results from the review’s constituent trials cannot be separated or recategorized based on procedure and content. Physical/exercise Physical activities, such as walking groups, gardening, or aerobics. Leisure/skill development Skill development or learning a new hobby. Structural Organizational (e.g., at workplace or school), community-based (e.g., volunteering), or societal (e.g., policy reform, awareness campaigns). This category refers more to the intervention setting. Mix/Other "Mix" was used only when applied by the systematic review and when interventions could not be separated or recategorized based on procedure and content. “Other” refers to types of interventions not matching the above categories. [Insert Table 1 about here] These non-mutually exclusive categories center on the interventions’ main objective and action mechanisms. While some interventions may incorporate elements from multiple categories, we presume that each primarily focuses on one area. The first two types can be regarded as “social” (or direct) interventions, as they aim directly at bolstering individuals’ social ties. In contrast, the next three are deemed “psychological” (or indirect) interventions, as they target cognitive and behavioral obstacles to social ties, teaching stress management strategies, and improving interpersonal interactions. The categories of computer/internet and digital interventions are overlapping, as are physical/exercise and leisure/skill development. Structural and mix/other interventions are open categories potentially encompassing a broad spectrum of strategies implemented at various levels. SRs were critically appraised using the Assessment of Multiple Systematic Reviews (AMSTAR) version 2 [ 42 ]. Based on the number of weaknesses in critical domains, we categorized the quality of reviews as moderate (0), low (1), and critically low (2+) (see Appendix 6). We applied a stringent interpretation of the criteria, and any item that was not fully met, including those rated as 'partial yes', was coded as 'no'. We assessed the overlap of SRs by comparing the list of included primary studies in each SR. A citation matrix was created with SRs in rows and primary studies in columns to count instances of repeated studies across SRs. This cross-referencing allowed visual inspection and quantification of overlap. We included all overlapping studies, as we were unable to limit inclusion to the highest quality or most comprehensive SR in the case of duplication. However, we report the extent of overlap and consider its possible impact during the interpretation of results. Data analysis and synthesis We grouped the SRs into those with quantitative (meta-analysis) and narrative synthesis analysis. We summarized and synthesized the findings of the two groups separately, and, where possible, according to the type of intervention and outcome. For meta-analyses, we present important parameters (effect size, heterogeneity, number of studies and participants, p-values). Effect sizes (including 95% confidence intervals), as reported by the SRs, are the standardized mean differences (SMD) or “Hedges’ g” which adjusts for small sample bias [ 43 ]. Unless otherwise stated, all effects refer to favorable (decreasing) changes in loneliness/isolation . SMD effect estimates ≤ 0.4 are interpreted as low/small effects, 0.40 to 0.70 as moderate, and > 0.7 as large effects [ 44 ]. Heterogeneity in pooled estimates is typically summarized using the I 2 statistic, which indicates how much of the variance can be attributed to between-study variation. I 2 values between 0 and 30% are interpreted as unimportant, 31–60% as moderate, 61–75% as substantial, and 76–100% as considerable [ 45 ]. There is no consensus on how to report findings from narrative synthesis [ 46 , 47 ]. Narrative synthesis provides direction of effect and a counting of significant effects. We have presented numerical data narratively using the metrics, where reported, from the SRs. However, as this information was often unavailable or not synthesized by the review authors (often due to the heterogeneity of the interventions and/or incomplete effect size data), we frequently only had the number of trials with significant effects (“vote count”) to rely on. It is generally recommended to avoid “vote counting”, e.g., counting effects that are statistically significant and favoring the intervention vs. all others [ 47 ]. This method has limitations and can lead to incorrect conclusions because underpowered studies that do not rule out clinically important effects are counted as not showing benefit. Additionally, it does not provide information on the magnitude of effects and does not account for differences in the relative sizes of the studies. In addition to the detailed findings, we provide tables with overall conclusions from the findings of the SRs using the “stop-light model” suggested by Aromataris et al. [ 48 ]. We use colors to indicate the overall conclusion regarding evidence of effect based solely on statistical significance. We additionally provide the effect size, number of respondents, and measure of heterogeneity, if available. The color red indicates no evidence of effect (for narrative synthesis; ≥75% of the trials show no significant effect), green indicates evidence of effect (for narrative synthesis; ≥75% of the trials show significant effect), and orange indicates inconsistent or inconclusive evidence of effect. Evidence based on only 1 RCT is regarded as inconclusive. Results Figure 1 summarizes the search results. After removing duplicates, the searches retrieved 2,935 records. Following title and abstract screening, 171 full-text articles were assessed for eligibility based on the inclusion criteria. A total of 29 SRs met our eligibility criteria. Appendix 4 displays the excluded publications and reasons for exclusion, as well as SRs (n = 14) identified from review protocols but for which we could not obtain the full text. Quality assessment Figure 2 displays the AMSTAR2 assessments for the included SRs. SR quality varied, with the number of weaknesses in critical domains ranging from none (4 SRs) to five (1 SR), and the most frequent quality score was one (10 SRs). The most common weaknesses in critical domains were the failure to pre-register a protocol, discuss the impact of risk of bias on results, provide a list of excluded studies and reasons for exclusion, and examine publication bias. Consequently, and considering our stringent criteria (coding “partially yes” as “no”), 4 SRs were classified as moderate, 10 as low, and 15 as critically low quality. The most common weaknesses in non-critical domains were failures to justify the choice of study selection and provide funding information for the included primary studies. [Insert Fig. 1 around here] [Insert Fig. 2 around here] The quality appraisal tool used varied across the reviews, with the Cochrane risk of bias tool emerging as the most frequently employed instrument, featured in 19 SRs (Table 3 ). There were five larger reviews (≥ 20 RCTs) that used this tool and reported the number of studies rated as having low, moderate, and high risk of bias [ 7 , 10 , 36 , 49 , 50 ]. On average, 21% of primary studies in the SRs were rated as low, 61% as moderate, and 17% as having a high risk of bias (own calculation). More specifically, the predominant concerns revolved around the procedures for randomization and allocation, the absence of blinding, participant attrition, and selective outcome reporting. The specific nature of the interventions often rendered the blinding of participants or personnel and volunteers unfeasible. Description of included reviews Key characteristics of the 29 included SRs are presented in Table 3 . The SRs were published from 2017, with the majority published since 2020 (22 SRs). Among the 29 SRs, 28 reported search dates, with the most recent searches being conducted up until 2020 (9 SRs), 2021 (2 SRs), and 2022 (4 SRs). The number of databases searched ranged from 3 to 10, with 5 − 7 databases being the most common (16 SRs). Grey literature was included in 10 SRs. Approximately equal numbers of SRs focused on all types of interventions (15 SRs) and specific types of interventions (14 SRs). Some reviews included all population groups (5 SRs), while others specifically targeted the young (4 SRs), adults (3 SRs), older adults (14 SRs), people with mental health problems (2 SRs), or cancer survivors (1 SR). The number of RCTs included in the reviews ranged from 2 to 58 ( 1,000 in 12 SRs, not reported in three SRs). All SRs focused on loneliness, with 12 SRs additionally focusing on social isolation. As Table 2 illustrates, the most frequently investigated interventions were psychological, digital, social contact, social support, and social skills training (all with ≥ 8 SRs). Eight SRs encompassed a mix of various intervention types (for meta-analysis; pooled analysis across intervention types). Table 2 Number of included systematic reviews with meta-analysis or narrative synthesis by type of intervention. Type of intervention Number of systematic reviews per intervention type Meta-analysis Narrative analysis Total Psychological/therapy 10 9 19 Digital (incl. computer/internet) 5 4 9 Diverse types 5 3 8 Social contact/network 3 5 8 Social support 6 2 8 Social skills training 3 4 7 Other 1 5 2 7 Psychoeducation 2 4 6 Leisure/skill development 1 1 2 Physical/exercise 1 — 1 Structural — — — Total 2 41 34 75 1 Multicomponent intervention (5 reviews), music, health and social care. 2 The total exceeds the number of included SRs, as each SR may cover multiple intervention types. The assessment of overlap in primary studies across the included SRs is detailed in Appendix 7. Of 256 primary studies in the SRs, 163 (64%) were “unique” and reviewed by only one SR, 49 (19%) by two SRs, and 45 (18%) by at least three SRs. Some additional features of the SRs, not shown in the tables, deserve mention. Typically, loneliness was measured using the UCLA Loneliness scale [ 51 ], the De Jong Gierveld Loneliness Scale [ 52 ], or single item measures. Social isolation was gauged by different measures, and the most frequently used was the Lubben Social Network Scale [ 53 ]. None of the SRs were Cochrane reviews. Further details about each type of intervention are discussed below. [Insert Table 2 about here] [Insert Table 3 about here] Table 3 Characteristics of included systematic reviews. Search and eligibility criteria Characteristics of included RCTs Study Objective Number of data-bases searched Grey literature sources searched Years searched Population details Number of RCTs Number of parti-cipants Outcome Quality appraisal: tool/rating (number of RCTs) Abbott 2019 To determine the effects of robopets on the health and well-being of older people living in care homes. 13 No Inception-2018 Older people living in care homes/residential care 2 82 Loneliness NR/Low, High quality Barnett 2020 To synthesize evidence to improve social circumstances across eight social domains in people with mental health conditions. 6 No 2000–2020 Adults aged 18 + with any mental health condition. Only high-income countries. 23 2,550 Objective/ subjective isolation Cochrane RoB Tool/ Low (5), Moderate (13), High (5) quality. Choi 2021 To investigate the effect of information communication technology interventions on loneliness among the elderly. 3 No 2003–2019 Age 60+ 3 370 Loneliness Cochrane RoB Tool/NR 1 Christensen 2021/Lasgaard 2022 To evaluate and compare the effectiveness of different interventions to reduce loneliness. 6 Yes 1980–2020 All ages 54 6,379 Loneliness Cochrane RoB Tool/: Low (12), Moderate (33), High (9) quality. GRADE: Low (≤ 4 weeks) 2 and Moderate (5–26 weeks) Eccles 2021 To examine the effect of interventions to reduce loneliness in young people, and moderators of the effects 4 No 1980-Jan 2020 Age ≤ 25 25 6,750 Loneliness Tools created by the National Heart, Lung, and Blood Institute and Research Triangle Institute/Poor (11), Fair (7), Good (7) 3 Ellard 2022 To assess the effectiveness of interventions addressing loneliness in university students 4 Yes Inception-March 2022 University students 16 NR Loneliness Cochrane RoB Tool v.2/NR Forsman 2018 To assess the effectiveness of technology-based interventions in promoting the mental health and wellbeing of older adults. 7 Yes 2003–2014 Age 65 + or age 55 + and retired 6 752 Loneliness NICE/Poor (2), Fair (2), Good (2) Fu 2022 To evaluate the effects of remotely delivered intervention on loneliness among older adults. 5 No Inception-July 2021 Age 65+ 13 1,045 Loneliness Cochrane RoB Tool/NR 1 Gardiner 2018 To determine the effectiveness of interventions targeting social isolation and loneliness. 6 Yes 2003–2016 Age 55+ 6 1,112 Loneliness, social isolation Hierarchy of evidence (score 3 to 9 (high quality)). Studies with score < 4 excluded/ Scores 7 (1), 8 (1), 9 (4) 4 Hao 2023 To understand the effectiveness of telehealth interventions on psychological outcomes in community adults during COVID-19 6 Yes 2019-Oct 2022 Community-dwelling adults aged 18+ 4 495 Loneliness Cochrane RoB Tool v.2/NR Heins 2021 To provide a comprehensive overview of the effects of technological interventions that address social participation in community-dwelling older adults with dementia. 5 No 2000- June 2020 Community-dwelling adults aged 55+ 3 170 Loneliness, social interaction Effective Public Health Practice Project/Moderate to strong quality. Hickin 2021 To explore the effect of psychological interventions to reduce loneliness across the lifespan, and the moderator of this effectiveness. 5 No 2000–2020 Entire population, age range 8–80; Mean 45 31 3,959 Loneliness Cochrane RoB Tool/ Low (10), Moderate (12), High (9) quality. Hoang 2022 To evaluate interventions targeting older adults to reduce social isolation and loneliness. 7 No Inception-March 2020 Age 65+ 70 8,259 Social isolation and loneliness Cochrane RoB Tool/NR GRADE “very low” for each of 10 intervention types Jin 2021 To determine the effectiveness of technology-based interventions for reducing loneliness in older adults. 7 No Inception-April 2021 Age 60+ 6 391 Loneliness Cochrane RoB Tool/ Low (3), Moderate (3) quality. Li 2018 To synthesize existing studies and provide an overall picture on the social effects of exergames on older adults. 4 No Inception -Jan 2017 Age 55+ 4 282 Loneliness Cochrane RoB Tool/ Low (2), Moderate or unclear (2) quality. Ma 2020 To review the evidence for the effectiveness of interventions to improve subjective and/or objective social isolation for people with mental health problems. 3 Yes Inception -July 2017 People with mental health problems 30 3,080 Subjective and objective social isolation Cochrane RoB Tool/ NR 1 McElfresh 2021 To determine the effectiveness of loneliness interventions among adult cancer survivors 7 No Inception-May 2019 Cancer survivors aged 18+ 7 465 Loneliness Downs and Black Tool/Low (1), High (2), Very high (4) quality. Osborn 2021 To assess the acceptability and effectiveness of interventions to reduce and prevent social isolation and loneliness in young people. 6 No NR Populations that include persons aged 10–25 5 411 Loneliness Mixed Method Appraisal Tool/NR 1 Poscia 2018 To summarize knowledge on the effectiveness of interventions for alleviating social isolation and loneliness among older persons. 5 No 2011-Feb 2016 Age 65+ 2 94 Loneliness, social isolation The Effective Public Health Practice Project Tool/Low quality Quan 2020 To review and compare evidence from the past 10 years on the effect of loneliness interventions for older adults living in long-term care facilities. 3 No 2009-Jan 2019 Adults aged 65 + living in LTC facilities 5 NR Loneliness, social isolation The Quality Assessment of Controlled Intervention Studies/High quality Shah 2021 To assess the effectiveness of digital technology interventions in reducing loneliness in older adults. 5 No 2010-July 2019 Age 18+ 5 459 Loneliness Cochrane RoB Tool/ High quality (5). GRADE by month of FU: 3m = moderate, 4m = very low, 6m = moderate. Shvedko 2018 To examine the physical activity intervention effects on loneliness, social isolation and low social support in community-dwelling older adults. 5 Yes 1946–2017 Community-dwelling, healthy/ cognitively intact, older adults aged 60+ 7 NR Loneliness, social isolation, social network Cochrane Review Book Group RoB tool/Score 4 to 8 (range 0–12) for the 7 RCTs Siette 2017 To evaluate the evidence for the effectiveness of befriending across a range of health conditions and clinical and social outcomes. 9 Yes Inception-2017 All populations 5 1,033 Loneliness Cochrane RoB Tool/ Low (1), Moderate (1), High (3) quality. Teoh 2021 To determine the effectiveness and safety of mindfulness-based interventions in alleviating loneliness. 5 No Inception-May 2020 All populations 8 815 Loneliness Cochrane RoB tool v2/Low (7), Moderate (1) quality. GRADE: Low Tong 2021 To summarize knowledge on the effectiveness of interventions for alleviating social isolation of older adults. 10 No 1978–2021 Adults aged 50 + with no mental illness or cognitive impairment. 24 4,078 Loneliness, social isolation Cochrane RoB tool/ Moderate (17), High (7) quality. Williams 2021 To identify and assess the effectiveness of interventions to reduce social isolation and loneliness that are compatible with COVID-19 shielding and social distancing measures. 6 Yes Inception-April 2020 Non-hospitalized persons of any age. 45 NR Loneliness, social isolation Downs and Black Tool/NR 1,5 Wiwatkunu-pakarn 2021 To examine the relationship between social network site usage and social isolation, loneliness, and depression among older adults. 3 No Inception-2020 Age 60+ 4 551 Loneliness, social isolation Cochrane RoB Tool/ NR 1 Zagic 2021 To determine the effect of interventions designed to promote ‘objective social contact’ and the ‘quality of social connections’. 4 No 1980–2020 Age 18+ 58 8,780 Objective social contact, perceived quality of social connection Cochrane RoB Tool v2/Low (6), Moderate (45), High (7) quality 6 Zhang 2023 To determine the effectiveness of psychological and exercise interventions compared with no treatment for problematic mobile phone use in RCTs 10 Yes Inception-Aug 2022 Chinese middle-school/university students with problematic mobile phone use 8 1,107 Loneliness Cochrane RoB Tool/ NR Notes: Abbreviations: RoB = Risk of bias, NR = not reported, FU = Follow-up. 1 Detailed (but no overall) ratings provided in the paper. 2 GRADE = Moderate in all subgroup analyses by type of intervention. 3 Reported per type of intervention (# Poor-Fair-Good): Support (0-4-0), social skills (2-0-3), social and emotional skills (5-1-1), psychological (2-3-3), learning hobby (2-0-0) 4 Psychological (all: High (score 9 of 9)), animal-assisted (Score 7/8 out of 9) 5 Reported per type of intervention (# Poor-Fair-Good). Social facilitation (3-2-5), Support (1-2-0), psychological (0-5-5), psychoeducation (0-3-1), Animal-assisted (1-2-0), Health/social care (0-1-1), Leisure/skill development (14-2-1) 6 Reported per type of intervention (# Poor-Fair-Good). Social access (1-11-3), Support (3-11-1), Social skills (0-2-0), psychological (0-8-4) Summary of results Detailed results for each type of intervention are provided in Tables 4 a- 4 g, as well as in summarized Tables 5 a- 5 g using the stop-light model. The effects of interventions were quantified as SMD or Hedges’ g with 95% confidence intervals in 13 meta-analyses and were subject to narrative synthesis in terms of significance testing and sometimes mean differences in 13 SRs. Overall, the extent to which the SRs provided details about populations, comparators, delivery (individual vs. group), mode (face-to-face, internet, etc.), frequency and duration, and follow-up measurement varied greatly. An overall summary of the certainty of the evidence (GRADE) was reported by only four SRs [ 40 , 53 – 55 ]. A review of 54 RCTs focusing on loneliness for diverse populations reported a low GRADE rating for the overall (pooled) evidence and a moderate rating for RCTs within each of five intervention types [ 40 ]. Another review of 70 RCTs targeting older adults reported a “very low” rating for each of ten intervention types focusing on social isolation and loneliness [ 53 ]. In general, there was no evidence or reporting that interventions did any harm. We summarize the evidence for each type of intervention below. The category “structural interventions” is excluded from this summary due to a lack of findings. Furthermore, due to a substantial overlap in their respective constituent interventions, digital interventions and computer/internet interventions have been consolidated into a single category. Mixed interventions In some SRs, evidence derived from diverse types of intervention was analyzed through pooled meta-analysis or narrative synthesis precluding the possibility of structuring the evidence by intervention type. We identified 5 such SRs with meta-analyses [ 10 , 32 , 40 , 56 , 57 ] and 3 SRs with narrative syntheses [ 36 , 58 , 59 ] (Table 4 a and Table 5 a). The SRs with narrative synthesis focused on older adults [ 36 , 58 ] or people with mental health problems [ 59 ]. These SRs show inconclusive evidence for social isolation [ 36 , 59 ] and inconclusive or no evidence of an effect on loneliness [ 36 , 58 , 59 ]. The 5 SRs with meta-analyses focused on the general population [ 10 , 40 , 56 ], younger persons [ 32 ], or cancer survivors [ 57 ]. The analyses show small to moderate effects of the aggregated (pooled) interventions on social isolation [ 10 ] and loneliness [ 10 , 32 , 40 , 56 , 57 ]. The meta-analysis on social isolation found evidence of a moderate effect (g = 0.43 [0.21; 0.65], I 2 = 46%, 10 RCTs) [ 10 ]. For loneliness, the largest meta-analysis covering 54 RCTs found a moderate effect (SMD = -0.47 [-0.61; -0.33], I 2 = 83%), but also considerable heterogeneity. Four SRs with meta-analysis of loneliness explored moderation effects (Table 4 a). With respect to sustainability of effects, one review reported moderate, considerably heterogeneous effects both in the short term (≤ 4 weeks; SMD − 0.47 [-0.61; -0.33], 54 studies, I 2 = 83%) and long-term (5–26 weeks; SMD − 0.49 [-0.76; -0.23], 18 studies, I 2 = NR) [ 40 ]. Another review of 13 studies found a small effect at < 3 months (SMD − 0.33 [-0.52; -0.14], I 2 50%), but not at > 6 months (SMD 0.37 [-0.02; 0.76], I 2 = NR). Moreover, SRs showed no statistically significant variation in effects across age groups [ 40 ], delivery (group vs. individual) [ 40 , 56 ], mode (face-to-face vs. digital) [ 40 ], or study quality [ 32 , 40 ]. Finally, while the effect sizes tended to be highest and most often statistically significant for psychological and educational interventions, the moderating role of intervention type was not statistically significant [ 32 , 56 , 60 ]. [Insert Table 4 a and 5 a about here] Social contact/network interventions These interventions often used an activity-based group format such as community groups, choirs, or exercise groups. These activities were typically delivered either in-person or through digital platforms, often scheduled on a weekly or bi-weekly basis, with a duration ranging from 4 to 52 weeks [ 7 , 56 ]. We identified 3 SRs with meta-analysis [ 10 , 40 , 56 ] and 5 SRs with narrative synthesis [ 50 , 59 , 61 – 63 ] including social contact/network interventions (Tables 4 b and 5 b). The SRs with narrative synthesis have focused on various populations [ 61 ], university students [ 63 ], older adults [ 62 ], or people with mental health problems [ 50 , 59 ]. Of the three narrative syntheses for social isolation (each with ≤ 3 RCTs), two showed evidence of effect [ 50 , 59 ] and one showed inconclusive results [ 61 ]. Of the five narrative syntheses of loneliness, three (each with ≤ 6 RCTs) showed inconclusive results [ 59 , 61 , 62 ], evidence of effect (4 RCTs) among university students [ 63 ], and (8 RCTs) no evidence of effect [ 50 ]. The three reviews with meta-analyses had various sample populations. One SR (4 RCTs) focused on social isolation and showed a considerably heterogeneous ( I 2 = 79%) moderate effect (g -0.67 [-0.98; -0.36]) [ 10 ]. Three SRs (6‒15 RCTs) reported on loneliness, and all showed substantial heterogeneity in the effects ( I 2 ≥ 60%). Two of the SRs found no evidence of effect [ 10 , 56 ], and one found a small effect (SMD − 0.30 [-0.50; -0.09]) [ 40 ]. None of the SRs addressed long-term effects. [Insert Table 4 b/5b about here] Social support interventions Social support interventions were primarily befriending efforts delivered individually. Typically, these interventions were facilitated by a volunteer and scheduled on a weekly or bi-weekly basis spanning up to one year. The mode of delivery varied, taking place either in-person or through digital platforms [ 32 , 53 ]. Six meta-analyses and two narrative syntheses reported on social support interventions (Table 4 c and Table 5 c). As the narrative syntheses [ 61 , 63 ] incorporated only 1–2 RCTs (n = 171 − 331) for each outcome, the conclusions drawn regarding the effects remain uncertain. Only one SR with meta-analysis (4 RCTs) focused on social isolation, showing a small non-significant effect (g 0.29 [-0.09; 0.67], I 2 = 49%) within mixed populations [ 10 ]. Six SRs with meta-analysis addressed loneliness, of which two focused on populations of all ages based on 10 [ 10 ] and 22 [ 40 ] RCTs, one on younger people (4 RCTs) [ 32 ], and three on older adults (3–5 RCTs) [ 53 , 56 , 64 ]. The effects were inconsistent with four SRs showing no evidence of effects and two reporting small-moderate effects that were moderately to substantially heterogeneous (SMD − 0.39 [-0.56; -0.23], I 2 ≥ 65% [ 40 ]; SMD − 0.47 [-0.77; -0.18], I 2 = 42% [ 56 ]). [Insert Table 4 c/5c about here] Psychological interventions Psychological interventions most frequently involve cognitive-behavioral therapy (CBT) and mindfulness-based stress-reduction [ 50 , 65 ]. A few used reminiscence therapy for older adults and animal-assisted therapy, where participants interacted with either live dogs or robotic animals such as seals or dogs [ 66 ]. Most interventions were delivered individually, with some opting for group settings. These were more often delivered face-to-face than digitally, according to the SRs providing such details [e.g., 32, 49, 56]. The frequency and duration of interventions varied as well, typically occurring weekly or biweekly, with durations ranging from a few weeks to up to a year. Follow-up effects were largely unaddressed. Based on 15 SRs (some with multiple analyses for different subgroups), the evidence on psychological interventions included 10 meta-analyses and 9 narrative syntheses (Table 4 d and 5 d). Population groups varied widely across reviews, with five addressing a mixed population [ 10 , 40 , 49 , 55 , 61 ], three targeting younger people [ 32 , 63 , 67 ], five targeting older adults [ 41 , 53 , 56 , 66 , 68 ], and two focusing on people with mental health concerns [ 50 , 59 ]. Four SRs focused on social isolation, all employing narrative synthesis [ 50 , 53 , 59 , 61 ]. Based on 4 RCTs, these reviews presented inconclusive or no evidence of effects. Among the eight reviews with narrative syntheses on loneliness, conclusions were also mixed and based on few (2 − 7) RCTs. Some of the evidence showed effect, among university students [ 63 ] or older adults in long-term care [ 41 , 68 ]. Others reported inconclusive evidence, in mixed populations [ 61 ], among people with mental health issues [ 50 , 59 ], young adults [ 41 , 67 , 68 ], and older adults [ 41 , 61 ]. Of the 10 SRs with meta-analyses on the effect of psychological interventions to reduce loneliness, seven showed benefits [ 10 , 32 , 40 , 49 , 53 , 55 , 56 ]. Three SRs based on few (2 − 4) RCTs reported small to moderate effects that were not significant [ 53 , 55 , 66 ]. The seven showing effects included up to 31 RCTs and the effects were generally moderate-large in size and substantially to considerably heterogeneous ( I 2 ≥ 65%). For example, the SR of 31 RCTs found a moderate effect (SMD 0.43 [0.18; 0.68, I 2 = 90%) [ 49 ]. The power of the meta-analyses is crucial as despite the pooled analyses showing significant effects, approximately half of their constituent RCTs did not [see 32, 55, 66, 69]. Two SRs reported a GRADE certainty of the evidence; the resulting grades were 'low' [ 55 ] and 'moderate' [ 70 ]. [Insert Table 4 d/5d about here] Psychoeducation interventions Psychoeducation interventions typically involved educating individuals at risk of loneliness (e.g., due to mental health issues) about topics relevant to loneliness or health more generally (Tables 4 e and 5 e). These interventions were addressed in two meta-analyses [ 40 , 53 ] and four narrative syntheses [ 50 , 59 , 61 , 63 ]. Three SRs did not report population details, and others focused on younger people [ 63 ], older adults [ 53 ], or people with mental health problems [ 50 , 59 ]. The narrative syntheses reported inconclusive evidence for benefits of psychoeducational interventions to reduced social isolation [ 59 ] or loneliness [ 50 , 59 , 61 , 63 ]. The meta-analyses on the effects of psychoeducational interventions for loneliness were reported as having a small effect (SMD − 0.19 [-0.35; -0.03], I 2 = 0%) and a large effect (SMD − 1.12 [-2.61; -0.36], I 2 = 65%), the latter with substantial heterogeneity. The SRs contained sparse additional intervention details, and none included follow-up data. [Insert Table 4 e/5e about here] Social skills interventions Social skills interventions were primarily delivered in-person, adopting a group format, and typically held on a weekly basis. The duration of these interventions varied, ranging from six weeks to a year. These interventions were explored in two SRs [ 32 , 40 ] with three meta-analyses and four SRs with narrative synthesis [ 10 , 50 , 59 , 67 ] (Tables 4 f and 5 f). Of these, two SRs included diverse populations [ 10 , 40 ], two focused on people with mental health issues [ 50 , 59 ], and two focused on younger people at risk of loneliness such as those diagnosed with Autism Spectrum Diagnosis (ASD), social phobia, or other mental health conditions [ 32 , 67 ]. Two of the SRs focused on social isolation using narrative syntheses, each based on 2–3 RCTs. One reported inconclusive outcomes [ 59 ], and the other reported beneficial effects [ 50 ]. Three other SRs with narrative synthesis focused on effects on loneliness, with two reporting inconclusive evidence (based on 2–4 RCTs) [ 10 , 59 ] and one reporting effects (2 RCTs) [ 67 ]. Three meta-analyses indicated the effect of social skills interventions on loneliness. One such analysis showed a small and considerably heterogeneous effect (SMD − 0.38 [-0.62; -0.15], I 2 > 65%), with the GRADE certainty of evidence rated as “moderate” [ 40 ]. One SR on young persons performed a separate analysis for “at-risk” groups (g 0.44 [0.10; 0.79], I 2 NR, 5 RCTs) and for children under age 15 (g 0.27 [-0.01; 0.53], I 2 NR, 7 RCTs), demonstrating a moderate effect of social skills interventions on loneliness in the former group [ 32 ]. [Insert Table 4 f/5f about here] Digital interventions Eight SRs, each based on a few (1 − 8) RCTs, investigated digital interventions among older adults (Tables 4 g and 5 g). These interventions included computer training, online interaction and support, gaming, and other internet-mediated approaches. These interventions were delivered both in groups and individually, usually with 1 − 3 sessions per week and for a period of one to six months [ 53 , 71 ]. One SR, with two narrative syntheses based on 1 − 2 RCTs, focused on social isolation and showed inconclusive evidence [ 72 ]. Four SRs with narrative synthesis focused on loneliness. These SRs demonstrated varying outcomes. No evidence of effect was found from 6 RCTs on information and communication technology (ICT) training and gaming [ 71 ], inconclusive evidence was found based on 1 − 3 RCTs evaluating online support or therapy [ 72 , 73 ], and evidence of effect was found on gaming and exercise (4 RCTs) [ 74 ]. Four SRs with meta-analysis showed no evidence of effect [ 53 , 54 , 75 , 76 ], while one SR of two RCTs among individuals in long-term care showed a large and substantially heterogeneous effect (SMD − 1.40 [-2.37; -0.44], I 2 = 70%). Assessment of long-term effects was largely absent, with the exception of two SRs [ 54 , 72 ] that included a total of 8 RCTs, and demonstrated no evidence of effects at various time points, up to one year. [Insert Table 4 g/5g about here] Other interventions We found five SRs that included a total of 10 analyses, including seven meta-analyses, of intervention types outside the above categories (see Appendix 8). Two SRs explored the effect of leisure and skill development, yielding inconclusive or null effects on social isolation and loneliness [ 32 , 61 ]. One SR, adopting a narrative synthesis of two RCTs, found no effect of health and social care service interventions on loneliness [ 61 ]. A further SR with meta-analysis on the effects of group-based exercise interventions among older adults, found no effect on social isolation or loneliness [ 53 ]. One review examined music interventions, including choir participation and music therapy, and reported a small effect on loneliness (SMD − 0.34 [-0.55; -0.13], 1 RCT), but no effect on social isolation (2 RCTs) [ 53 ]. Two SRs evaluated interventions that combined psychotherapy and exercise. One of the reviews focused on older adults and found no evidence of effect for either social isolation or loneliness [ 77 ]. The other SR involving young Chinese individuals reported a large effect (SMD − 1.10 [-1.45; -0.71], 8 RCTs) on loneliness [ 65 ]. One SR assessed the effect of multicomponent interventions (various combinations) among older adults [ 53 ]. In community settings, there was a small effect on social isolation (SMD 0.29 [0.15; 0.43], I 2 = 0%, 6 RCTs) and a moderate effect on loneliness (SMD − 0.67 [-1.13; -0.21], I 2 NR, 2 RCTs), and in long-term care settings, there was a moderate effect on loneliness (SMD − 0.53 [-0.86; -0.20], I 2 = 57%, 3 RCTs). Discussion The aim of the present UR was to synthesize and critically appraise systematic reviews of RCT-based evidence on the effectiveness of SIL interventions. The evidence showed that social interventions promoting social contact and providing social support are effective strategies to tackle social isolation. In contrast, psychological interventions hold the most promise for mitigating loneliness. The quality of the evidence varies greatly, and effect sizes are typically being small to moderate and displaying substantial to considerable heterogeneity. The heterogeneity can be attributed to multiple factors, including varying intervention components such as frequency, duration, setting, and content, as well as methodological limitations such as risk of bias and small sample sizes. There was no reporting that interventions did any harm, but we are uncertain whether the primary studies measured any adverse events, or if this is an oversight from SRs authors. Our overall findings confirm and strengthen the conclusions of previous URs, providing an updated and robust evidence base. We have enriched our understanding by encompassing recent evidence and by also factoring in social isolation, which mirrors the health implications of loneliness. By narrowing our focus to RCTs — often hailed as the "gold standard" and highest level of evidence — and supplementing with grey literature to potentially capture a broader scope of non-significant outcomes, we aim to fortify and elevate the overall evidence base. Why and how social interventions hold particular promise for mitigating social isolation can be offered several interpretations. Substantial evidence suggests that interventions aimed at providing social support or fostering friendships and social activity show promise in reducing social isolation, especially in the short term [ 10 , 50 , 61 ]. However, the long-term impacts remain uncertain [ 59 ]. Sustainability is critical, as the immediate effect can be deemed self-evident or even tautological; the presence of social support inherently implies a reduction in social isolation . Although some well-powered meta-analyses with many RCTs and participants show small positive impacts of social interventions also on loneliness, the overall evidence shows no or inconsistent effects, suggesting a lesser and more uncertain impact on loneliness. This uncertainty suggests that increasing social contact does not necessarily alleviate loneliness unless accompanied by psychological changes [ 10 ]. Issues such as mistrust, negative self-beliefs, hypersensitivity to social threat and rejection, and social anxiety often intertwine with or underpin loneliness [ 59 ], hindering the formation and maintenance of close social relationships. For some, new social situations might bring discomfort and self-consciousness, potentially intensifying feelings of isolation rather than mitigating loneliness. Likewise, while compassionate social support and companion resources in befriending interventions can yield significant anticipatory and experienced rewards for some, as qualitative studies indicate [ 64 , 78 ], for others, it may highlight, stigmatize, and patronize their loneliness, exacerbating rather than reducing it. These ideas suggest that merging social interventions with psychological elements can enhance efficacy, addressing psychological issues while nurturing social relationships in a safe environment [ 33 , 61 ]. Why and how psychological and educational interventions show more potential for reducing loneliness than social isolation can be interpreted in various ways. The moderate to large positive effects often exhibited for psychological interventions on loneliness may reflect that they address the cognitive-behavioral underlying roots of loneliness. Psychological-educational interventions address some of the same barriers and components, focusing on providing lessons on making friends and addressing barriers to social integration [ 49 ]. Part of the success may also stem from the fact that the interventions target cognitive biases and avoidance behavior that underlie not only loneliness, but also mental health problems that co-exist with or underpin loneliness, such as depressive mood, anxiety, low self-worth, and social withdrawal [ 7 ]. Hence, the effect may be indirect by targeting the barriers to secure social connection. Their success likely also stems from being directed mainly or exclusively toward individuals who are either lonely or at risk of loneliness due to underlying psychological issues or conditions (e.g., ASD). The evidence for the effects from other types of interventions was small and inconsistent. For instance, the few SRs centered on physical activities, learning new hobbies, and health and social care services reported no evidence of effect. Digital interventions have increased in popularity in recent years and may help people stay connected with family and friends and access information or receive social support in online communities. To date, the evidence on their effectiveness for addressing SIL is uncertain. This uncertainty could reflect the highly diverse nature of digital interventions, and the fact that they have targeted older adults. While older adults are becoming more adept with technology and online communication, a significant portion may still face challenges navigating these platforms and might find such communication unsatisfying [ 79 ]. Moderation effects and subgroup heterogeneity were examined in mixed types of interventions. Only a few SRs examined longer-term effects and the results were inconsistent. For example, while one SR demonstrated that long-term effects (i.e., one to six months after the intervention) were comparable to the short-term effects (i.e., up to four weeks after the intervention) [ 7 ], another SR found evidence of effect for up to 6 months but not thereafter [ 56 ]. Furthermore, no difference in the overall effectiveness was shown for group vs. individual settings [ 30 , 32 , 40 , 56 , 60 ], between digital and non-digital interventions [ 7 , 32 , 40 ], between studies of high, moderate and low quality [ 7 , 32 , 40 ], or depending on age groups [ 7 , 32 , 40 ] or gender [ 32 ]. The relative similarity of effects across subgroups implies that various approaches and strategies can be employed to reduce loneliness without a significant difference in outcomes. The overlap of primary studies in the results can introduce redundancy and potentially skew findings. However, in the current overview, the impact appears to be minimal due to the low degree of overlap, ensuring that the results remain predominantly independent. Limitations of the research evidence and implications for future research This UR reveals several gaps and limitations in the literature, indicating areas for future research and interventions. For instance, studies need to assess interventions for young people, the persistence of intervention effects, and social isolation, which parallels loneliness in health impacts. Furthermore, there is a pressing need to evaluate broader structural determinants and interventions of SIL [ 15 , 80 ], using observational studies or natural experiments, because RCTs may be unsuitable for these approaches. Their absence in our UR could stem from our focus on RCTs, but notably, no structural interventions were found during our broad screening across all study designs. Furthermore, trials often lack clear theoretical bases, hindering the identification of active elements that reduce loneliness. For instance, in mindfulness-based therapies, the effective factor is unclear and could be meditation, breath-work, presence, group interaction, or increased thought awareness. Similarly, it is often unclear whether interventions target lonely individuals or those presumed at risk [ 32 , 49 , 53 ], requiring more clarity in future intervention design and evaluation [ 29 ]. Another limitation we encountered is the quality of the trials and systematic reviews. Many trials lack adequate blinding procedures, randomization processes, and power, increasing the risk of type-I error. Furthermore, the quality of SRs is often low. Many reviews fail to preregister protocols, to use scientific quality appropriately in formulating conclusions, to specify interventions in adequate detail, and to use clear categories of interventions. These problems partly reflect the lack of detail reported in the primary studies. Meta-analysis on pooled data of highly diverse types of interventions is also problematic, as evidenced by the substantial heterogeneity of their effects. Such an approach also curtails the applicability of the results for practical purposes. Additionally, narrative synthesis within the SRs relied excessively on p-values, whereas reporting numerical data, effect sizes, and precision are preferable [ 29 ]. Furthermore, combining dissimilar interventions in meta-analyses compromises the practical relevance of the pooled estimates due to the diversity of interventions [ 81 ]. Although some SRs include subgroup analyses, the lack of differentiation by intervention types limits the practical application of the acquired knowledge [ 10 ]. Beyond structural interventions, other types of interventions also seem largely unexplored. For example, it is worth noting the potency of giving support to address one’s own social disconnection. Positive psychology interventions have long recognized that giving (generosity, prosociality) is often more powerful than receiving, challenging the assumption that people must always be on the receiving end of an intervention to address SIL. Volunteering and digital interventions, through group interactions and online forums, offer unique and flexible opportunities for reciprocal support, fostering meaningful connections and positive relationships. Integrating elements from different approaches to treat individuals holistically and individually is another avenue for future research. Given the heterogeneity of the population of lonely people, it is essential to tailor interventions to different types of loneliness, triggers, and risk groups [ 29 , 53 ]. For instance, those whose loneliness is rooted in insecure attachment or mental health issues might need interventions focusing on cognitive and other barriers. On the other hand, people with situational loneliness may benefit from interventions aimed at enhancing social networks and connectedness. In response to the question of common misconceptions about ways to enhance happiness, bestselling author Gretchen Rubin asserted that the fundamental mistake people make is to believe that there is a single, universally effective method [ 82 ]. She emphasized that happiness-enhancing strategies are profoundly individualistic, contingent on one's unique nature, interests, values, and idiosyncrasies. This perspective mirrors our own and others’ [e.g., 10, 60] notions regarding mitigating SIL, dispelling the idea of a one-size-fits-all solution and instead advocating for tailored and individual-centric strategies. In the rapidly evolving digital era, the exploration of ways to improve technology-based interventions for social isolation and loneliness becomes increasingly vital. Balancing these limitations were several strengths, including the use of rigorous methods and quality assessment, grouping SRs by type of intervention and outcome, the exclusive focus on RCTs, and the broad search strategy including grey literature to contribute valuable insights to the field and inform future research and practice in addressing social isolation and loneliness. CONCLUSION There is an urgent need to develop a comprehensive, evidence-based understanding and effective remedies for SIL. However, the current evidence from SRs does not yet clearly support any specific intervention to reduce SIL. Potential interventions such as cognitive modification for loneliness and support and facilitated socialization for social isolation show promise, but the quality of published trials and SRs limits our confidence in their findings and our ability to draw firm conclusions. Compounding this uncertainty is the inconsistency within the findings, paired with our limited insight regarding the exact 'active ingredients' that bring about successful results, the interventions’ relevance to different subgroups, and the circumstances under which they perform optimally. We suggest that high-quality research and innovation in intervention development informed by the limitations identified in this UR should be prioritized. 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Barnett P, Steare T, Dedat Z, Pilling S, McCrone P, Knapp M, Cooke E, Lamirel D, Dawson S, Goldblatt P. Interventions to improve social circumstances of people with mental health conditions: a rapid evidence synthesis. BMC psychiatry 2022, 22(1):1–68. Russell D, Peplau LA, Cutrona CE. The revised UCLA Loneliness Scale: concurrent and discriminant validity evidence. Journal of Personality and Social Psychology 1980, 39(3):472. de-Jong Gierveld J, Van Tilburg T. The De Jong Gierveld short scales for emotional and social loneliness: tested on data from 7 countries in the UN generations and gender surveys. European Journal of Ageing 2010, 7(2):121–130. Hoang P, King JA, Moore S, Moore K, Reich K, Sidhu H, Tan CV, Whaley C, McMillan J. Interventions Associated With Reduced Loneliness and Social Isolation in Older Adults: A Systematic Review and Meta-analysis. JAMA Network Open 2022, 5(10):e2236676-e2236676. Shah SGS, Nogueras D, van Woerden HC, Kiparoglou V. Evaluation of the effectiveness of digital technology interventions to reduce loneliness in older adults: systematic review and meta-analysis. Journal of Medical Internet Research 2021, 23(6):e24712. Teoh SL, Letchumanan V, Lee L-H. Can mindfulness help to alleviate loneliness? A systematic review and meta-analysis. Frontiers in Psychology 2021, 12:633319. Fu Z, Yan M, Meng C. The effectiveness of remote delivered intervention for loneliness reduction in older adults: A systematic review and meta-analysis. Frontiers in Psychology 2022, 13:935544–935544. McElfresh JJ, Skiba MB, Segrin CG, Badger TA, Crane TE, Crist JD, Thomson CA. Interventions for Loneliness Among Adult Cancer Survivors: A Systematic Review and Meta-Analysis. Journal of Psychosocial Oncology 2021, 39(4):509–533. Poscia A, Stojanovic J, La Milia DI, Duplaga M, Grysztar M, Moscato U, Onder G, Collamati A, Ricciardi W, Magnavita N. Interventions targeting loneliness and social isolation among the older people: An update systematic review. Experimental Gerontology 2018, 102:133–144. Ma R, Mann F, Wang J, Lloyd-Evans B, Terhune J, Al-Shihabi A, Johnson S. The effectiveness of interventions for reducing subjective and objective social isolation among people with mental health problems: a systematic review. Social Psychiatry and Psychiatric Epidemiology 2020, 55(7):839–876. Lasgaard M, Løvschall C, Qualter P, Laustsen L, Lim M, Maindal H, Hargaard A, Christensen J. Are loneliness interventions effective in reducing loneliness? A meta-analytic review of 128 studies: Mathias Lasgaard. European Journal of Public Health 2022, 32. Williams CY, Townson AT, Kapur M, Ferreira AF, Nunn R, Galante J, Phillips V, Gentry S, Usher-Smith JA. Interventions to reduce social isolation and loneliness during COVID-19 physical distancing measures: A rapid systematic review. PloS one 2021, 16(2):e0247139. Wiwatkunupakarn N, Pateekhum C, Aramrat C, Jirapornchaoren W, Pinyopornpanish K, Angkurawaranon C. Social networking site usage: A systematic review of its relationship with social isolation, loneliness, and depression among older adults. Aging & Mental Health 2022, 26(7):1318–1326. Ellard OB, Dennison C, Tuomainen H. Interventions addressing loneliness amongst university students: a systematic review. Child and Adolescent Mental Health 2021. Siette J, Cassidy M, Priebe S. Effectiveness of befriending interventions: a systematic review and meta-analysis. BMJ open 2017, 7(4):e014304. Zhang K, Lu X, Zhang X, Zhang J, Ren J, Guo H, Zhu Z, Yang H, Yuan G, Jin G. Effects of Psychological or Exercise Interventions on Problematic Mobile Phone Use: a Systematic Review and Meta-analysis. Current Addiction Reports 2023:1–24. Abbott R, Orr N, McGill P, Whear R, Bethel A, Garside R, Stein K, Thompson-Coon J. How do “robopets” impact the health and well‐being of residents in care homes? A systematic review of qualitative and quantitative evidence. International Journal of Older People Nursing 2019, 14(3):e12239. Osborn T, Weatherburn P, French RS. Interventions to address loneliness and social isolation in young people: A systematic review of the evidence on acceptability and effectiveness. Journal of Adolescence 2021, 93:53–79. Quan NG, Lohman MC, Resciniti NV, Friedman DB. A systematic review of interventions for loneliness among older adults living in long-term care facilities. Aging & Mental Health 2020, 24(12):1945–1955. Williams T, Lakhani A, Spelten E. Interventions to reduce loneliness and social isolation in rural settings: a mixed-methods review. Journal of Rural Studies 2022, 90:76–92. Christensen K, Doblhammer G, Rau R, Vaupel JW. Ageing populations: the challenges ahead. The lancet 2009, 374(9696):1196–1208. Forsman AK, Nordmyr J, Matosevic T, Park A-L, Wahlbeck K, McDaid D. Promoting mental wellbeing among older people: technology-based interventions. Health Promotion International 2018, 33(6):1042–1054. Heins P, Boots LM, Koh WQ, Neven A, Verhey FR, de Vugt ME. The effects of technological interventions on social participation of community-dwelling older adults with and without dementia: A systematic review. Journal of Clinical Medicine 2021, 10(11):2308. Choi H, Lee S: Trends and Effectiveness of ICT Interventions for the Elderly to Reduce Loneliness: A Systematic Review. Healthcare 2021, 9, 293. Li J, Erdt M, Chen L, Cao Y, Lee S-Q, Theng Y-L. The social effects of exergames on older adults: systematic review and metric analysis. Journal of Medical Internet Research 2018, 20(6):e10486. Hao X, Qin Y, Lv M, Zhao X, Wu S, Li K: Effectiveness of telehealth interventions on psychological outcomes and quality of life in community adults during the COVID-19 pandemic: A systematic review and meta-analysis. International Journal of Mental Health Nursing. Jin W, Liu Y, Yuan S, Bai R, Li X, Bai Z. The effectiveness of technology-based interventions for reducing loneliness in older adults: A systematic review and meta-analysis of randomized controlled trials. Frontiers in Psychology 2021, 12. Shvedko A, Whittaker AC, Thompson JL, Greig CA. Physical activity interventions for treatment of social isolation, loneliness or low social support in older adults: A systematic review and meta-analysis of randomised controlled trials. Psychology of Sport and Exercise 2018, 34:128–137. Preston C, Moore S. Ringing the changes: the role of telephone communication in a helpline and befriending service targeting loneliness in older people. Ageing & Society 2019, 39(7):1528–1551. Oh SS, Kim K-A, Kim M, Oh J, Chu SH, Choi J. Measurement of digital literacy among older adults: systematic review. Journal of Medical Internet Research 2021, 23(2):e26145. Pitman A, Mann F, Johnson S. Advancing our understanding of loneliness and mental health problems in young people. The Lancet Psychiatry 2018, 5(12):955–956. Borenstein M, Hedges LV, Higgins JP, Rothstein HR. Introduction to meta-analysis: John Wiley & Sons; 2021. Rubin G. “The Happiness Lab by Laurie Santos” podcast. 29 May 2023. Footnotes Clearly defined inclusion criteria regarding population, type of intervention, and outcomes. We did not require a clearly defined comparator, given their highly diverse nature in this field. The form we created for data extraction included explanations for each item and their categories. We piloted the form with two systematic reviews to ensure authors consistently extracted the same data using the same categories for the variables of interest. Three SRs (10, 32, 47) express reductions in SIL with positively valanced effect sizes. Social interventions spanned a few weeks to a maximum of one year in duration. However, data on long-term effects and post-intervention follow-ups was largely unavailable. Tables 3-5 Tables 3-5 are available in the Supplementary Files section. Appendices Appendices 1-8 are not available with this version. Supplementary Files Tabes3to5.docx Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-3351098","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Systematic Review","associatedPublications":[],"authors":[{"id":232746804,"identity":"fe2513ea-54f6-4c14-a865-d9a5972ac77e","order_by":0,"name":"Thomas Hansen","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA1klEQVRIiWNgGAWjYDACCQiVAKEq5BLYCOngQdVyxphULYxtxgkE3WUv3Xx0w48/DHn8s9sfPi6cZ5DHx8B78AFeW2SOpd3sbWMolrhzxth45jaDYjYGvmQD/A7LMbvB28CQ2HAjh02ad9ufxDYGHjMJQlpu/vnDkDj/Rvrz37xzDIjTcpuHjSFxw40EM2beBmK03EhLuy3bJpG48UaOsTTPMaAWZh5jvH5hn5F87OabPzaJ826kP/zMU2OQOL+9x/ABPi1QgOwSZiLUj4JRMApGwSjADwBKZkUJt1XldgAAAABJRU5ErkJggg==","orcid":"https://orcid.org/0000-0001-7529-9252","institution":"Norwegian Institute of Public Health","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Thomas","middleName":"","lastName":"Hansen","suffix":""},{"id":232746805,"identity":"3436143a-8855-4d93-9e6b-6159268d33ba","order_by":1,"name":"Ragnhild Bang Nes","email":"","orcid":"","institution":"Norwegian Institute of Public Health","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Ragnhild","middleName":"Bang","lastName":"Nes","suffix":""},{"id":232746806,"identity":"e33c9a7d-156d-4398-8a2f-57f5606d8d00","order_by":2,"name":"Kamila Hynek","email":"","orcid":"","institution":"Norwegian Institute of Public Health","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Kamila","middleName":"","lastName":"Hynek","suffix":""},{"id":232746807,"identity":"9b17c2c8-97b6-47fe-ad45-64482156b2a0","order_by":3,"name":"Thomas S. Nilsen","email":"","orcid":"","institution":"Norwegian Institute of Public Health","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Thomas","middleName":"S.","lastName":"Nilsen","suffix":""},{"id":232746808,"identity":"196703d2-c9a5-44e9-9e44-edb448bb135b","order_by":4,"name":"Anne Reneflot","email":"","orcid":"","institution":"Norwegian Institute of Public Health","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Anne","middleName":"","lastName":"Reneflot","suffix":""},{"id":232746809,"identity":"85a4806b-0bc0-43dd-9023-1e89a7c668e6","order_by":5,"name":"Kim Stene-Larsen","email":"","orcid":"","institution":"Norwegian Institute of Public Health","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Kim","middleName":"","lastName":"Stene-Larsen","suffix":""},{"id":232746810,"identity":"08324003-07ab-4abf-a149-8b268dc84d2c","order_by":6,"name":"Ragnhild Tornes","email":"","orcid":"","institution":"Norwegian Institute of Public Health","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Ragnhild","middleName":"","lastName":"Tornes","suffix":""},{"id":232746811,"identity":"e4ab98c7-ad1e-4a19-9000-393e02b8eb07","order_by":7,"name":"Julia Bidonde","email":"","orcid":"","institution":"Norwegian Institute of Public Health","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Julia","middleName":"","lastName":"Bidonde","suffix":""}],"badges":[],"createdAt":"2023-09-13 08:15:22","currentVersionCode":1,"declarations":{"humanSubjects":false,"vertebrateSubjects":false,"conflictsOfInterestStatement":true,"humanSubjectEthicalGuidelines":false,"humanSubjectConsent":false,"humanSubjectClinicalTrial":false,"humanSubjectCaseReport":false,"vertebrateSubjectEthicalGuidelines":false,"coiExplicitlySet":false},"doi":"10.21203/rs.3.rs-3351098/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-3351098/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":43207213,"identity":"5131e7f0-c779-430e-8d9b-86b014cfccdd","added_by":"auto","created_at":"2023-09-15 17:48:22","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":886362,"visible":true,"origin":"","legend":"\u003cp\u003ePRISMA flow diagram of the search screening process.\u003c/p\u003e","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-3351098/v1/495bebb75840226a52676b90.jpeg"},{"id":43207898,"identity":"f2c6859d-a0fc-46bd-b909-cd4ec5116cb2","added_by":"auto","created_at":"2023-09-15 17:56:22","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":5713,"visible":true,"origin":"","legend":"\u003cp\u003eLegend not included with this version.\u003c/p\u003e","description":"","filename":"Placeholderimage.png","url":"https://assets-eu.researchsquare.com/files/rs-3351098/v1/85e79734a1c155787bd458f7.png"},{"id":43207899,"identity":"efdd412f-3382-4385-8438-f4ffd0aa3198","added_by":"auto","created_at":"2023-09-15 17:56:28","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1122824,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-3351098/v1/ba27090f-a364-41a0-b403-123c6fd309a0.pdf"},{"id":43207211,"identity":"20388e0d-abc7-4bc3-9dca-55eb08cc3ac4","added_by":"auto","created_at":"2023-09-15 17:48:22","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":82704,"visible":true,"origin":"","legend":"","description":"","filename":"Tabes3to5.docx","url":"https://assets-eu.researchsquare.com/files/rs-3351098/v1/32537ca361065fc5f93f264a.docx"}],"financialInterests":"","formattedTitle":"\u003cp\u003e\u003cstrong\u003eTackling social disconnection: An umbrella review of RCT-based interventions targeting social isolation and loneliness\u003c/strong\u003e\u003c/p\u003e","fulltext":[{"header":"Introduction","content":"\u003cp\u003eSocial isolation and loneliness (SIL) are pervasive and serious public health concerns associated with numerous detrimental physical and mental health outcomes, including mortality [\u003cspan additionalcitationids=\"CR2 CR3\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Associations also extend to adverse impacts on prosocial behavior (e.g., volunteering), social participation, healthcare utilization, productivity, and daily functioning [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Thus, SIL generates a wide array of harmful and debilitating effects, ranging from individual suffering to broader societal burdens and financial costs.\u003c/p\u003e \u003cp\u003eSocial isolation and loneliness, although conceptually similar, are distinct and moderately correlated phenomena [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Social isolation (\u0026ldquo;being alone\u0026rdquo;) refers to an objective state characterized by limited social contacts and infrequent meaningful contact with others [\u003cspan additionalcitationids=\"CR9\" citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. In contrast, loneliness (\u0026ldquo;feeling alone\u0026rdquo;) is a subjective experience and refers to the negative feeling caused by a discrepancy between actual and desired social connection and social contact [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. The prevalence of social isolation varies across its specific indicators, but generally increases in later life [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. For instance, over one-third of adults aged 65 and above, and more than half of those aged over 80, live alone in Norway and several other Western countries [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Loneliness is also a widespread issue in Western countries, with approximately one-quarter of the adult population reporting that they \u0026ldquo;sometimes\u0026rdquo; or \u0026ldquo;often\u0026rdquo; feel lonely [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. The proportion is even higher among the youngest and oldest age groups and a significant increase among adolescents and young adults has been documented in many Western countries over recent decades [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Among older age groups, the rates appear relatively stable, yet the absolute rates will in many countries likely rise in the future due to the aging of the population [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eStrategies are sought globally to prevent and alleviate SIL [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. To this end, access to high-quality research evaluating intervention effectiveness is crucial. Although the development and evaluation of SIL interventions are still in their infancy compared to interventions for mental and physical health problems [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e], the evidence base is rapidly expanding, accompanied by an increasing number of published systematic reviews (SRs). However, the quality and scope of SRs often vary, in terms of the focal intervention type, populations, delivery format, or outcome, making it challenging to obtain a comprehensive overview of an intervention\u0026rsquo;s effectiveness [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. To address this limitation, systematic reviews of systematic reviews (termed umbrella reviews (URs)) can be conducted. URs systematically assess, and synthesize evidence from multiple SRs [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e], to offer a comprehensive examination of the available information, allowing for a more robust evaluation of intervention effectiveness [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eWe identified six URs of interventions for reducing SIL [\u003cspan additionalcitationids=\"CR27 CR28 CR29 CR30\" citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]. These have conflicting findings, making it challenging to draw firm conclusions. Two suggest that interventions have small but significant effects [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e], or that specific interventions such as mindfulness, social cognitive training, and social support are effective while others, such as befriending, technological interventions, and social training interventions, are not [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]. The other four URs conclude that interventions generally show no effect [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e] or, based on digital interventions, show weak and inconsistent effects [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. Factors contributing to these diverse findings include different study designs (randomized controlled trials (RCTs) and non-RCTs) and varying quality of evidence and reviews. Half of the URs are not published in peer-reviewed journals. Additionally, the pooling of analyses involving widely different types of interventions and populations further contributes to the challenges in synthesizing the evidence (see Appendix 1 for a detailed description of prior and current umbrella reviews).\u003c/p\u003e \u003cp\u003eFurthermore, these URs reveal several knowledge gaps. Limited research has been conducted on adolescents and younger adults, despite the increasing prevalence of loneliness among these age groups. Only half of the URs also addressed social isolation, which has health impacts similar to loneliness [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. The evidence also remains scarce for specific types of interventions. For example, the UR supporting the benefits of mindfulness is based on only two RCTs [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]. Non-RCTs and single group (pre-post) designs raise concerns related to internal validity and have been shown to significantly overestimate effect sizes compared to RCTs [\u003cspan additionalcitationids=\"CR33 CR34\" citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]. Synthesizing RCT-based evidence is necessary to provide a more reliable and accurate evaluation of intervention efficacy [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]. Encouragingly, the number of RCT-evaluated interventions has increased in recent years, and the quality of RCTs appears to be improving [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e]. This highlights the need for a further UR to update the evidence and address these limitations.\u003c/p\u003e \u003cp\u003eThe aim of this UR is to synthesize and critically appraise scientific evidence on the effectiveness of SIL interventions. This UR includes all types of preventive and mitigating interventions for individuals of all ages, including children and youth. It adds to the existing UR literature by (i) only including SRs of RCTs, (ii) including only the most recent SRs (2017\u0026ndash;2023), (iii) considering both published and non-published (grey) literature, (iv) analyzing overall and subgroup effects by intervention type), and (v) assessing both social isolation and loneliness. Our goal is to provide updated and valuable insights for researchers, policymakers, and practitioners in this field.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003eThis UR was registered with PROSPERO (CRD42022329192) and is reported according to the Preferred Reporting Items for Overview of Reviews (PRIOR) reporting guideline (see Appendix 2) [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. One deviation from the protocol involved excluding an eligible SR [\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e] since it included only one relevant RCT, which had already been included in three other included SRs.\u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eInclusions and exclusion criteria\u003c/h2\u003e \u003cp\u003eEligible SRs were written in English or Scandinavian languages and published in 2017 or later. SRs were required to have a clear PICO\u003ca class=\"FNLink\" href=\"#Fn1\" id=\"#FNLinkFn1\"\u003e\u003c/a\u003e, a search of two or more databases, and an assessment of risk of bias. Eligible SRs needed to include data from RCTs and provide intervention data (e.g., effect size), with data provided separately for RCTs if non-RCT data were also included. Reviews of any population and any non-pharmacological types of preventive/mitigating intervention (e.g., befriending, social support, psychological interventions) were eligible. Any comparison treatment was acceptable (e.g., treatment-as-usual, other treatment, no care). Reviews including measures of the following outcomes were eligible: loneliness and/or social isolation (or close proxy measures, e.g., social contact). We excluded SRs that did not focus on social isolation or loneliness, SRs that did not measure or report effects comparatively, and SRs using other designs (e.g., scoping reviews).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eSearch methods\u003c/h2\u003e \u003cp\u003eAn information specialist (RAT) conducted a systematic literature search based on a search strategy that combined text words and controlled vocabulary (e.g., MEDLINE Medical Subject Headings), applying a method filter for SRs (see full search strategy in Appendix 3). The strategy was peer-reviewed by a second information specialist. The strategy was adapted for the following databases: MEDLINE (OVID), Embase (OVID), APA PsycINFO (OVID), Sociological Abstracts (ProQuest), CINAHL (EBSCO), Web of Science Core Collection databases (SCI-EXPANDED, SSCI, A\u0026amp;HCI, and ESCI), and Epistemonikos. The search was performed on June 16\u0026ndash;17, 2022, and updated on 19 June, 2023. Grey literature was identified through searches in Google Scholar, Swemed+, Prospero, Open Grey System for Information on Grey Literature in Europe, OAIster, and The Campbell Collaboration on June, 20\u0026ndash;21, 2022 (updated 22 June 2023). We also contacted researchers with relevant expertise for suggestions of SRs and searched reference lists of included SRs and prior URs (see Appendix 3).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eScreening and selection of reviews\u003c/h2\u003e \u003cp\u003eSearch results were imported into EndNote [\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e], where records were de-duplicated. The results were loaded into Covidence [\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e] for screening. Titles, abstracts, and full-text articles were screened by two review authors independently, with disagreements resolved through discussion. Reasons for excluding full-text SRs were recorded (Appendix 4). When protocols for SRs were identified, up to three emails were sent to the authors requesting copies of the completed SRs. In the absence of a response, the study was excluded from the UR (see Appendix 5).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003eData extraction and quality assessment\u003c/h2\u003e \u003cp\u003ePairs of authors conducted data extraction and quality assessment independently, with disagreements resolved through discussion. An Excel data extraction form was developed and piloted for this project\u003ca class=\"FNLink\" href=\"#Fn2\" id=\"#FNLinkFn2\"\u003e\u003c/a\u003e. For each SR, data on the research question (aim), search strategy (number of databases, grey literature (no/yes), years covered), population, RCT characteristics (number, origin, sample size, sample characteristics (mean age, mental disorder, institutionalized vs. community dwelling, etc. ), outcomes and outcome measures, and review characteristics (Cochrane review (no/yes), GRADE assessment (no/yes), risk of bias/quality assessment measure), and results were extracted. We extracted data on intervention characteristics and findings, grouped, if possible, by type of intervention. This included the type of intervention (see below), nature of the intervention (procedure used), delivery format (group vs. individual), comparator(s), mode of delivery (face-to-face, internet, etc.), intervention provider (e.g., therapist, health worker), setting (e.g., long-term care), frequency and duration of intervention, follow-up details, author/year of included primary studies, and findings (e.g., overall and subgroup effects). Inspired by previous categorizations [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e, \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e, \u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e], interventions were pre-classified into 11 groups in the data extraction sheet (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eIntervention categories (used in the data extraction form)\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSocial network and contact\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePromoting social contact and activity, expanding network size, providing opportunities for social interaction (e.g., online or group-based meeting or activities, video-calls with family, friendship clubs, shared interest groups, day care centers).\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSocial support\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eProviding social support through regular contact, care, or companionship (e.g., befriending) typically conducted by a volunteer or peer mentor. Unlike \u0026lsquo;social network and contact\u0026rsquo;, which focuses on reciprocity and mutual benefit, this category is more one-directional.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003ePsychological/therapy\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAddressing social cognition or providing psychological support to cope with distress (e.g., psychotherapy, cognitive-behavioral therapy, mindfulness). The goal is to tackle negative thoughts and beliefs, influence social behavior and self-efficacy, and reduce barriers to socialization and secure social connections. Usually delivered by a trained therapist or health professional.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003ePsychoeducation\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eEducation about topics related to loneliness, health, and well-being more broadly.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSocial skills training\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eEducational interventions focused on improving friendship, communication, and interpersonal skills.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eComputer/internet\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTraining in the use of information and communication technology, such as internet, email, and social media platforms.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eDigital\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDigitally delivered (e.g., video-conferencing, online support groups). Applied only when used by the systematic reviews and when results from the review\u0026rsquo;s constituent trials cannot be separated or recategorized based on procedure and content.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003ePhysical/exercise\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePhysical activities, such as walking groups, gardening, or aerobics.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eLeisure/skill development\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSkill development or learning a new hobby.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eStructural\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOrganizational (e.g., at workplace or school), community-based (e.g., volunteering), or societal (e.g., policy reform, awareness campaigns). This category refers more to the intervention setting.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eMix/Other\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\"Mix\" was used only when applied by the systematic review and when interventions could not be separated or recategorized based on procedure and content. \u0026ldquo;Other\u0026rdquo; refers to types of interventions not matching the above categories.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e[Insert Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e about here]\u003c/p\u003e \u003cp\u003eThese non-mutually exclusive categories center on the interventions\u0026rsquo; main objective and action mechanisms. While some interventions may incorporate elements from multiple categories, we presume that each primarily focuses on one area. The first two types can be regarded as \u0026ldquo;social\u0026rdquo; (or direct) interventions, as they aim directly at bolstering individuals\u0026rsquo; social ties. In contrast, the next three are deemed \u0026ldquo;psychological\u0026rdquo; (or indirect) interventions, as they target cognitive and behavioral obstacles to social ties, teaching stress management strategies, and improving interpersonal interactions. The categories of computer/internet and digital interventions are overlapping, as are physical/exercise and leisure/skill development. Structural and mix/other interventions are open categories potentially encompassing a broad spectrum of strategies implemented at various levels.\u003c/p\u003e \u003cp\u003eSRs were critically appraised using the Assessment of Multiple Systematic Reviews (AMSTAR) version 2 [\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e]. Based on the number of weaknesses in critical domains, we categorized the quality of reviews as moderate (0), low (1), and critically low (2+) (see Appendix 6). We applied a stringent interpretation of the criteria, and any item that was not fully met, including those rated as 'partial yes', was coded as 'no'.\u003c/p\u003e \u003cp\u003eWe assessed the overlap of SRs by comparing the list of included primary studies in each SR. A citation matrix was created with SRs in rows and primary studies in columns to count instances of repeated studies across SRs. This cross-referencing allowed visual inspection and quantification of overlap. We included all overlapping studies, as we were unable to limit inclusion to the highest quality or most comprehensive SR in the case of duplication. However, we report the extent of overlap and consider its possible impact during the interpretation of results.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003eData analysis and synthesis\u003c/h2\u003e \u003cp\u003eWe grouped the SRs into those with quantitative (meta-analysis) and narrative synthesis analysis. We summarized and synthesized the findings of the two groups separately, and, where possible, according to the type of intervention and outcome. For meta-analyses, we present important parameters (effect size, heterogeneity, number of studies and participants, p-values). Effect sizes (including 95% confidence intervals), as reported by the SRs, are the standardized mean differences (SMD) or \u0026ldquo;Hedges\u0026rsquo; g\u0026rdquo; which adjusts for small sample bias [\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e]. Unless otherwise stated, all effects refer to favorable (decreasing) changes in loneliness/isolation\u003ca class=\"FNLink\" href=\"#Fn3\" id=\"#FNLinkFn3\"\u003e\u003c/a\u003e. SMD effect estimates\u0026thinsp;\u0026le;\u0026thinsp;0.4 are interpreted as low/small effects, 0.40 to 0.70 as moderate, and \u0026gt;\u0026thinsp;0.7 as large effects [\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e]. Heterogeneity in pooled estimates is typically summarized using the \u003cem\u003eI\u003c/em\u003e\u003csup\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sup\u003e statistic, which indicates how much of the variance can be attributed to between-study variation. \u003cem\u003eI\u003c/em\u003e\u003csup\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sup\u003e values between 0 and 30% are interpreted as unimportant, 31\u0026ndash;60% as moderate, 61\u0026ndash;75% as substantial, and 76\u0026ndash;100% as considerable [\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThere is no consensus on how to report findings from narrative synthesis [\u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e, \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e]. Narrative synthesis provides direction of effect and a counting of significant effects. We have presented numerical data narratively using the metrics, where reported, from the SRs. However, as this information was often unavailable or not synthesized by the review authors (often due to the heterogeneity of the interventions and/or incomplete effect size data), we frequently only had the number of trials with significant effects (\u0026ldquo;vote count\u0026rdquo;) to rely on. It is generally recommended to avoid \u0026ldquo;vote counting\u0026rdquo;, e.g., counting effects that are statistically significant and favoring the intervention vs. all others [\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e]. This method has limitations and can lead to incorrect conclusions because underpowered studies that do not rule out clinically important effects are counted as not showing benefit. Additionally, it does not provide information on the magnitude of effects and does not account for differences in the relative sizes of the studies.\u003c/p\u003e \u003cp\u003eIn addition to the detailed findings, we provide tables with overall conclusions from the findings of the SRs using the \u0026ldquo;stop-light model\u0026rdquo; suggested by Aromataris et al. [\u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e48\u003c/span\u003e]. We use colors to indicate the overall conclusion regarding evidence of effect based solely on statistical significance. We additionally provide the effect size, number of respondents, and measure of heterogeneity, if available. The color red indicates no evidence of effect (for narrative synthesis; \u0026ge;75% of the trials show no significant effect), green indicates evidence of effect (for narrative synthesis; \u0026ge;75% of the trials show significant effect), and orange indicates inconsistent or inconclusive evidence of effect. Evidence based on only 1 RCT is regarded as inconclusive.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eFigure \u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e summarizes the search results. After removing duplicates, the searches retrieved 2,935 records. Following title and abstract screening, 171 full-text articles were assessed for eligibility based on the inclusion criteria. A total of 29 SRs met our eligibility criteria. Appendix 4 displays the excluded publications and reasons for exclusion, as well as SRs (n\u0026thinsp;=\u0026thinsp;14) identified from review protocols but for which we could not obtain the full text.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003eQuality assessment\u003c/h2\u003e \u003cp\u003eFigure 2 displays the AMSTAR2 assessments for the included SRs. SR quality varied, with the number of weaknesses in critical domains ranging from none (4 SRs) to five (1 SR), and the most frequent quality score was one (10 SRs). The most common weaknesses in critical domains were the failure to pre-register a protocol, discuss the impact of risk of bias on results, provide a list of excluded studies and reasons for exclusion, and examine publication bias. Consequently, and considering our stringent criteria (coding \u0026ldquo;partially yes\u0026rdquo; as \u0026ldquo;no\u0026rdquo;), 4 SRs were classified as moderate, 10 as low, and 15 as critically low quality.\u003c/p\u003e \u003cp\u003eThe most common weaknesses in non-critical domains were failures to justify the choice of study selection and provide funding information for the included primary studies.\u003c/p\u003e \u003cp\u003e[Insert Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e around here]\u003c/p\u003e \u003cp\u003e[Insert Fig.\u0026nbsp;2 around here]\u003c/p\u003e \u003cp\u003eThe quality appraisal tool used varied across the reviews, with the Cochrane risk of bias tool emerging as the most frequently employed instrument, featured in 19 SRs (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e3\u003c/span\u003e). There were five larger reviews (\u0026ge;\u0026thinsp;20 RCTs) that used this tool and reported the number of studies rated as having low, moderate, and high risk of bias [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e, \u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e, \u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e]. On average, 21% of primary studies in the SRs were rated as low, 61% as moderate, and 17% as having a high risk of bias (own calculation). More specifically, the predominant concerns revolved around the procedures for randomization and allocation, the absence of blinding, participant attrition, and selective outcome reporting. The specific nature of the interventions often rendered the blinding of participants or personnel and volunteers unfeasible.\u003c/p\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003eDescription of included reviews\u003c/h2\u003e \u003cp\u003eKey characteristics of the 29 included SRs are presented in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e3\u003c/span\u003e. The SRs were published from 2017, with the majority published since 2020 (22 SRs). Among the 29 SRs, 28 reported search dates, with the most recent searches being conducted up until 2020 (9 SRs), 2021 (2 SRs), and 2022 (4 SRs). The number of databases searched ranged from 3 to 10, with 5\u0026thinsp;\u0026minus;\u0026thinsp;7 databases being the most common (16 SRs). Grey literature was included in 10 SRs.\u003c/p\u003e \u003cp\u003eApproximately equal numbers of SRs focused on all types of interventions (15 SRs) and specific types of interventions (14 SRs). Some reviews included all population groups (5 SRs), while others specifically targeted the young (4 SRs), adults (3 SRs), older adults (14 SRs), people with mental health problems (2 SRs), or cancer survivors (1 SR). The number of RCTs included in the reviews ranged from 2 to 58 (\u0026lt;\u0026thinsp;10 in 18 SRs). The total number of participants ranged from 82 to 8,780 (\u0026gt;\u0026thinsp;1,000 in 12 SRs, not reported in three SRs). All SRs focused on loneliness, with 12 SRs additionally focusing on social isolation.\u003c/p\u003e \u003cp\u003eAs Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e2\u003c/span\u003e illustrates, the most frequently investigated interventions were psychological, digital, social contact, social support, and social skills training (all with \u0026ge;\u0026thinsp;8 SRs). Eight SRs encompassed a mix of various intervention types (for meta-analysis; pooled analysis across intervention types).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eNumber of included systematic reviews with meta-analysis or narrative synthesis by type of intervention.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eType of intervention\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003eNumber of systematic reviews per intervention type\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMeta-analysis\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNarrative analysis\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eTotal\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePsychological/therapy\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e19\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDigital (incl. computer/internet)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDiverse types\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSocial contact/network\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSocial support\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSocial skills training\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOther\u003csup\u003e1\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePsychoeducation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLeisure/skill development\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePhysical/exercise\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u0026mdash;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eStructural\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u0026mdash;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u0026mdash;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u0026mdash;\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e41\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e75\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003e\u003csup\u003e1\u003c/sup\u003e Multicomponent intervention (5 reviews), music, health and social care. \u003csup\u003e2\u003c/sup\u003e The total exceeds the number of included SRs, as each SR may cover multiple intervention types.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eThe assessment of overlap in primary studies across the included SRs is detailed in Appendix 7. Of 256 primary studies in the SRs, 163 (64%) were \u0026ldquo;unique\u0026rdquo; and reviewed by only one SR, 49 (19%) by two SRs, and 45 (18%) by at least three SRs.\u003c/p\u003e \u003cp\u003eSome additional features of the SRs, not shown in the tables, deserve mention. Typically, loneliness was measured using the UCLA Loneliness scale [\u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e51\u003c/span\u003e], the De Jong Gierveld Loneliness Scale [\u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e52\u003c/span\u003e], or single item measures. Social isolation was gauged by different measures, and the most frequently used was the Lubben Social Network Scale [\u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e]. None of the SRs were Cochrane reviews. Further details about each type of intervention are discussed below.\u003c/p\u003e \u003cp\u003e[Insert Table \u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e2\u003c/span\u003e about here]\u003c/p\u003e \u003cp\u003e[Insert Table \u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e3\u003c/span\u003e about here]\u003c/p\u003e \u003c/div\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eCharacteristics of included systematic reviews.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"10\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colspan=\"4\" nameend=\"c6\" namest=\"c3\"\u003e \u003cp\u003eSearch and eligibility criteria\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"4\" nameend=\"c10\" namest=\"c7\"\u003e \u003cp\u003eCharacteristics of included RCTs\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eStudy\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eObjective\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNumber of data-bases searched\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eGrey literature sources searched\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eYears searched\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003ePopulation details\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eNumber of RCTs\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003eNumber of parti-cipants\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c9\"\u003e \u003cp\u003eOutcome\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c10\"\u003e \u003cp\u003eQuality appraisal: tool/rating (number of RCTs)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAbbott 2019\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTo determine the effects of robopets on the health and well-being of older people living in care homes.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eInception-2018\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eOlder people living in care homes/residential care\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e82\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eLoneliness\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eNR/Low, High quality\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBarnett 2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTo synthesize evidence to improve social circumstances across eight social domains in people with mental health conditions.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2000\u0026ndash;2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eAdults aged 18\u0026thinsp;+\u0026thinsp;with any mental health condition. Only high-income countries.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e2,550\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eObjective/ subjective isolation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eCochrane RoB Tool/\u003c/p\u003e \u003cp\u003eLow (5), Moderate (13), High (5) quality.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eChoi 2021\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTo investigate the effect of information communication technology interventions on loneliness among the elderly.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2003\u0026ndash;2019\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eAge 60+\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e370\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eLoneliness\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eCochrane RoB Tool/NR\u003csup\u003e1\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eChristensen 2021/Lasgaard 2022\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTo evaluate and compare the effectiveness of different interventions to reduce loneliness.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eYes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1980\u0026ndash;2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eAll ages\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e54\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e6,379\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eLoneliness\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eCochrane RoB Tool/:\u003c/p\u003e \u003cp\u003eLow (12), Moderate (33), High (9) quality.\u003c/p\u003e \u003cp\u003eGRADE: Low (\u0026le;\u0026thinsp;4 weeks)\u003csup\u003e2\u003c/sup\u003e and Moderate (5\u0026ndash;26 weeks)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEccles 2021\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTo examine the effect of interventions to reduce loneliness in young people, and moderators of the effects\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1980-Jan 2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eAge\u0026thinsp;\u0026le;\u0026thinsp;25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e6,750\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eLoneliness\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eTools created by the National Heart, Lung, and Blood Institute and Research Triangle Institute/Poor (11), Fair (7), Good (7)\u003csup\u003e3\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEllard 2022\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTo assess the effectiveness of interventions addressing loneliness in university students\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eYes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eInception-March 2022\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eUniversity students\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eNR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eLoneliness\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eCochrane RoB Tool v.2/NR\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eForsman 2018\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTo assess the effectiveness of technology-based interventions in promoting the mental health and wellbeing of older adults.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eYes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2003\u0026ndash;2014\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eAge 65\u0026thinsp;+\u0026thinsp;or age 55\u0026thinsp;+\u0026thinsp;and retired\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e752\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eLoneliness\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eNICE/Poor (2), Fair (2), Good (2)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFu 2022\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTo evaluate the effects of remotely delivered intervention on loneliness among older adults.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eInception-July 2021\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eAge 65+\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e1,045\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eLoneliness\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eCochrane RoB Tool/NR\u003csup\u003e1\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGardiner 2018\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTo determine the effectiveness of interventions targeting social isolation and loneliness.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eYes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2003\u0026ndash;2016\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eAge 55+\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e1,112\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eLoneliness, social isolation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eHierarchy of evidence (score 3 to 9 (high quality)). Studies with score\u0026thinsp;\u0026lt;\u0026thinsp;4 excluded/ Scores 7 (1), 8 (1), 9 (4)\u003csup\u003e4\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHao 2023\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTo understand the effectiveness of telehealth interventions on psychological outcomes in community adults during COVID-19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eYes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2019-Oct 2022\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eCommunity-dwelling adults aged 18+\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e495\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eLoneliness\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eCochrane RoB Tool v.2/NR\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHeins 2021\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTo provide a comprehensive overview of the effects of technological interventions that address social participation in community-dwelling older adults with dementia.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2000- June 2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eCommunity-dwelling adults aged 55+\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e170\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eLoneliness, social interaction\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eEffective Public Health Practice Project/Moderate to strong quality.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHickin 2021\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTo explore the effect of psychological interventions to reduce loneliness across the lifespan, and the moderator of this effectiveness.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2000\u0026ndash;2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eEntire population, age range 8\u0026ndash;80; Mean 45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e3,959\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eLoneliness\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eCochrane RoB Tool/\u003c/p\u003e \u003cp\u003eLow (10), Moderate (12), High (9) quality.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHoang 2022\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTo evaluate interventions targeting older adults to reduce social isolation and loneliness.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eInception-March 2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eAge 65+\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e70\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e8,259\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eSocial isolation and loneliness\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eCochrane RoB Tool/NR\u003c/p\u003e \u003cp\u003eGRADE \u0026ldquo;very low\u0026rdquo; for each of 10 intervention types\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eJin 2021\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTo determine the effectiveness of technology-based interventions for reducing loneliness in older adults.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eInception-April 2021\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eAge 60+\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e391\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eLoneliness\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eCochrane RoB Tool/\u003c/p\u003e \u003cp\u003eLow (3), Moderate (3) quality.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLi 2018\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTo synthesize existing studies and provide an overall picture on the social effects of exergames on older adults.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eInception -Jan 2017\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eAge 55+\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e282\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eLoneliness\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eCochrane RoB Tool/\u003c/p\u003e \u003cp\u003eLow (2), Moderate or unclear (2) quality.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMa 2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTo review the evidence for the effectiveness of interventions to improve subjective and/or objective social isolation for people with mental health problems.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eYes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eInception -July 2017\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003ePeople with mental health problems\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e3,080\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eSubjective and objective social isolation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eCochrane RoB Tool/ NR\u003csup\u003e1\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMcElfresh 2021\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTo determine the effectiveness of loneliness interventions among adult cancer survivors\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eInception-May 2019\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eCancer survivors aged 18+\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e465\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eLoneliness\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eDowns and Black Tool/Low (1), High (2), Very high (4) quality.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOsborn 2021\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTo assess the acceptability and effectiveness of interventions to reduce and prevent social isolation and loneliness in young people.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eNR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003ePopulations that include persons aged 10\u0026ndash;25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e411\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eLoneliness\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eMixed Method Appraisal Tool/NR\u003csup\u003e1\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePoscia 2018\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTo summarize knowledge on the effectiveness of interventions for alleviating social isolation and loneliness among older persons.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2011-Feb 2016\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eAge 65+\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e94\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eLoneliness, social isolation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eThe Effective Public Health Practice Project Tool/Low quality\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eQuan 2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTo review and compare evidence from the past 10 years on the effect of loneliness interventions for older adults living in long-term care facilities.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2009-Jan 2019\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eAdults aged 65\u0026thinsp;+\u0026thinsp;living in LTC facilities\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eNR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eLoneliness, social isolation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eThe Quality Assessment of Controlled Intervention Studies/High quality\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eShah 2021\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTo assess the effectiveness of digital technology interventions in reducing loneliness in older adults.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2010-July 2019\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eAge 18+\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e459\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eLoneliness\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eCochrane RoB Tool/\u003c/p\u003e \u003cp\u003eHigh quality (5).\u003c/p\u003e \u003cp\u003eGRADE by month of FU: 3m\u0026thinsp;=\u0026thinsp;moderate, 4m\u0026thinsp;=\u0026thinsp;very low, 6m\u0026thinsp;=\u0026thinsp;moderate.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eShvedko 2018\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTo examine the physical activity intervention effects on loneliness, social isolation and low social support in community-dwelling older adults.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eYes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1946\u0026ndash;2017\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eCommunity-dwelling, healthy/ cognitively intact, older adults aged 60+\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eNR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eLoneliness, social isolation, social network\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eCochrane Review Book Group RoB tool/Score 4 to 8 (range 0\u0026ndash;12) for the 7 RCTs\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSiette 2017\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTo evaluate the evidence for the effectiveness of befriending across a range of health conditions and clinical and social outcomes.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eYes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eInception-2017\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eAll populations\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e1,033\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eLoneliness\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eCochrane RoB Tool/\u003c/p\u003e \u003cp\u003eLow (1), Moderate (1), High (3) quality.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTeoh 2021\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTo determine the effectiveness and safety of mindfulness-based interventions in alleviating loneliness.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eInception-May 2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eAll populations\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e815\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eLoneliness\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eCochrane RoB tool v2/Low (7), Moderate (1) quality.\u003c/p\u003e \u003cp\u003eGRADE: Low\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTong 2021\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTo summarize knowledge on the effectiveness of interventions for alleviating social isolation of older adults.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1978\u0026ndash;2021\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eAdults aged 50\u0026thinsp;+\u0026thinsp;with no mental illness or cognitive impairment.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e4,078\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eLoneliness, social isolation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eCochrane RoB tool/\u003c/p\u003e \u003cp\u003eModerate (17), High (7) quality.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWilliams 2021\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTo identify and assess the effectiveness of interventions to reduce social isolation and loneliness that are compatible with COVID-19 shielding and social distancing measures.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eYes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eInception-April 2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNon-hospitalized persons of any age.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eNR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eLoneliness, social isolation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eDowns and Black Tool/NR\u003csup\u003e1,5\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWiwatkunu-pakarn\u0026nbsp;2021\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTo examine the relationship between social network site usage and social isolation, loneliness, and depression among older adults.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eInception-2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eAge 60+\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e551\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eLoneliness, social isolation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eCochrane RoB Tool/ NR\u003csup\u003e1\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eZagic 2021\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTo determine the effect of interventions designed to promote \u0026lsquo;objective social contact\u0026rsquo; and the \u0026lsquo;quality of social connections\u0026rsquo;.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1980\u0026ndash;2020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eAge 18+\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e58\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e8,780\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eObjective social contact, perceived quality of social connection\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eCochrane RoB Tool v2/Low (6), Moderate (45), High (7) quality\u003csup\u003e6\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eZhang 2023\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTo determine the effectiveness of psychological and exercise interventions compared with no treatment for problematic mobile phone use in RCTs\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eYes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eInception-Aug 2022\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eChinese middle-school/university students with problematic mobile phone use\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e1,107\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eLoneliness\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eCochrane RoB Tool/ NR\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"10\"\u003eNotes: Abbreviations: RoB\u0026thinsp;=\u0026thinsp;Risk of bias, NR\u0026thinsp;=\u0026thinsp;not reported, FU\u0026thinsp;=\u0026thinsp;Follow-up.\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"10\"\u003e\u003csup\u003e1\u003c/sup\u003e Detailed (but no overall) ratings provided in the paper.\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"10\"\u003e\u003csup\u003e2\u003c/sup\u003e GRADE\u0026thinsp;=\u0026thinsp;Moderate in all subgroup analyses by type of intervention.\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"10\"\u003e\u003csup\u003e3\u003c/sup\u003e Reported per type of intervention (# Poor-Fair-Good): Support (0-4-0), social skills (2-0-3), social and emotional skills (5-1-1), psychological (2-3-3), learning hobby (2-0-0)\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"10\"\u003e\u003csup\u003e4\u003c/sup\u003e Psychological (all: High (score 9 of 9)), animal-assisted (Score 7/8 out of 9)\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"10\"\u003e\u003csup\u003e5\u003c/sup\u003e Reported per type of intervention (# Poor-Fair-Good). Social facilitation (3-2-5), Support (1-2-0), psychological (0-5-5), psychoeducation (0-3-1), Animal-assisted (1-2-0), Health/social care (0-1-1), Leisure/skill development (14-2-1)\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"10\"\u003e\u003csup\u003e6\u003c/sup\u003e Reported per type of intervention (# Poor-Fair-Good). Social access (1-11-3), Support (3-11-1), Social skills (0-2-0), psychological (0-8-4)\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eSummary of results\u003c/h2\u003e \u003cp\u003eDetailed results for each type of intervention are provided in Tables\u0026nbsp;\u003cspan refid=\"Tab10\" class=\"InternalRef\"\u003e4\u003c/span\u003ea-\u003cspan refid=\"Tab10\" class=\"InternalRef\"\u003e4\u003c/span\u003eg, as well as in summarized Tables\u0026nbsp;\u003cspan refid=\"Tab17\" class=\"InternalRef\"\u003e5\u003c/span\u003ea-\u003cspan refid=\"Tab17\" class=\"InternalRef\"\u003e5\u003c/span\u003eg using the stop-light model. The effects of interventions were quantified as SMD or Hedges\u0026rsquo; g with 95% confidence intervals in 13 meta-analyses and were subject to narrative synthesis in terms of significance testing and sometimes mean differences in 13 SRs. Overall, the extent to which the SRs provided details about populations, comparators, delivery (individual vs. group), mode (face-to-face, internet, etc.), frequency and duration, and follow-up measurement varied greatly. An overall summary of the certainty of the evidence (GRADE) was reported by only four SRs [\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e, \u003cspan additionalcitationids=\"CR54\" citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e55\u003c/span\u003e]. A review of 54 RCTs focusing on loneliness for diverse populations reported a low GRADE rating for the overall (pooled) evidence and a moderate rating for RCTs within each of five intervention types [\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e]. Another review of 70 RCTs targeting older adults reported a \u0026ldquo;very low\u0026rdquo; rating for each of ten intervention types focusing on social isolation and loneliness [\u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e]. In general, there was no evidence or reporting that interventions did any harm.\u003c/p\u003e \u003cp\u003eWe summarize the evidence for each type of intervention below. The category \u0026ldquo;structural interventions\u0026rdquo; is excluded from this summary due to a lack of findings. Furthermore, due to a substantial overlap in their respective constituent interventions, digital interventions and computer/internet interventions have been consolidated into a single category.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003eMixed interventions\u003c/h2\u003e \u003cp\u003eIn some SRs, evidence derived from diverse types of intervention was analyzed through pooled meta-analysis or narrative synthesis precluding the possibility of structuring the evidence by intervention type. We identified 5 such SRs with meta-analyses [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e, \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e, \u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e, \u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e57\u003c/span\u003e] and 3 SRs with narrative syntheses [\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e, \u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e58\u003c/span\u003e, \u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e59\u003c/span\u003e] (Table\u0026nbsp;\u003cspan refid=\"Tab10\" class=\"InternalRef\"\u003e4\u003c/span\u003ea and Table\u0026nbsp;\u003cspan refid=\"Tab17\" class=\"InternalRef\"\u003e5\u003c/span\u003ea). The SRs with narrative synthesis focused on older adults [\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e, \u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e58\u003c/span\u003e] or people with mental health problems [\u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e59\u003c/span\u003e]. These SRs show inconclusive evidence for social isolation [\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e, \u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e59\u003c/span\u003e] and inconclusive or no evidence of an effect on loneliness [\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e, \u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e58\u003c/span\u003e, \u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e59\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe 5 SRs with meta-analyses focused on the general population [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e, \u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e], younger persons [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e], or cancer survivors [\u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e57\u003c/span\u003e]. The analyses show small to moderate effects of the aggregated (pooled) interventions on social isolation [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e] and loneliness [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e, \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e, \u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e, \u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e57\u003c/span\u003e]. The meta-analysis on social isolation found evidence of a moderate effect (g\u0026thinsp;=\u0026thinsp;0.43 [0.21; 0.65], \u003cem\u003eI\u003c/em\u003e\u003csup\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;46%, 10 RCTs) [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. For loneliness, the largest meta-analysis covering 54 RCTs found a moderate effect (SMD = -0.47 [-0.61; -0.33], \u003cem\u003eI\u003c/em\u003e\u003csup\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;83%), but also considerable heterogeneity.\u003c/p\u003e \u003cp\u003eFour SRs with meta-analysis of loneliness explored moderation effects (Table\u0026nbsp;\u003cspan refid=\"Tab10\" class=\"InternalRef\"\u003e4\u003c/span\u003ea). With respect to sustainability of effects, one review reported moderate, considerably heterogeneous effects both in the short term (\u0026le;\u0026thinsp;4 weeks; SMD \u0026minus;\u0026thinsp;0.47 [-0.61; -0.33], 54 studies, \u003cem\u003eI\u003c/em\u003e\u003csup\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;83%) and long-term (5\u0026ndash;26 weeks; SMD \u0026minus;\u0026thinsp;0.49 [-0.76; -0.23], 18 studies, \u003cem\u003eI\u003c/em\u003e\u003csup\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;NR) [\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e]. Another review of 13 studies found a small effect at \u0026lt;\u0026thinsp;3 months (SMD \u0026minus;\u0026thinsp;0.33 [-0.52; -0.14], \u003cem\u003eI\u003c/em\u003e\u003csup\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sup\u003e\u0026thinsp;\u0026lt;\u0026thinsp;50%) and at 3\u0026ndash;6 months (SMD \u0026minus;\u0026thinsp;0.32 [-0.57; -0.07], \u003cem\u003eI\u003c/em\u003e\u003csup\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sup\u003e\u0026thinsp;\u0026gt;\u0026thinsp;50%), but not at \u0026gt;\u0026thinsp;6 months (SMD 0.37 [-0.02; 0.76], \u003cem\u003eI\u003c/em\u003e\u003csup\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;NR). Moreover, SRs showed no statistically significant variation in effects across age groups [\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e], delivery (group vs. individual) [\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e, \u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e], mode (face-to-face vs. digital) [\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e], or study quality [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e, \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e]. Finally, while the effect sizes tended to be highest and most often statistically significant for psychological and educational interventions, the moderating role of intervention type was not statistically significant [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e, \u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e, \u003cspan citationid=\"CR60\" class=\"CitationRef\"\u003e60\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e[Insert Table \u003cspan refid=\"Tab10\" class=\"InternalRef\"\u003e4\u003c/span\u003ea and \u003cspan refid=\"Tab17\" class=\"InternalRef\"\u003e5\u003c/span\u003ea about here]\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003eSocial contact/network interventions\u003c/h2\u003e \u003cp\u003eThese interventions often used an activity-based group format such as community groups, choirs, or exercise groups. These activities were typically delivered either in-person or through digital platforms, often scheduled on a weekly or bi-weekly basis, with a duration ranging from 4 to 52 weeks [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eWe identified 3 SRs with meta-analysis [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e, \u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e] and 5 SRs with narrative synthesis [\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e, \u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e59\u003c/span\u003e, \u003cspan additionalcitationids=\"CR62\" citationid=\"CR61\" class=\"CitationRef\"\u003e61\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR63\" class=\"CitationRef\"\u003e63\u003c/span\u003e] including social contact/network interventions (Tables\u0026nbsp;\u003cspan refid=\"Tab10\" class=\"InternalRef\"\u003e4\u003c/span\u003eb and \u003cspan refid=\"Tab17\" class=\"InternalRef\"\u003e5\u003c/span\u003eb). The SRs with narrative synthesis have focused on various populations [\u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e61\u003c/span\u003e], university students [\u003cspan citationid=\"CR63\" class=\"CitationRef\"\u003e63\u003c/span\u003e], older adults [\u003cspan citationid=\"CR62\" class=\"CitationRef\"\u003e62\u003c/span\u003e], or people with mental health problems [\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e, \u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e59\u003c/span\u003e]. Of the three narrative syntheses for social isolation (each with \u0026le;\u0026thinsp;3 RCTs), two showed evidence of effect [\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e, \u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e59\u003c/span\u003e] and one showed inconclusive results [\u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e61\u003c/span\u003e]. Of the five narrative syntheses of loneliness, three (each with \u0026le;\u0026thinsp;6 RCTs) showed inconclusive results [\u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e59\u003c/span\u003e, \u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e61\u003c/span\u003e, \u003cspan citationid=\"CR62\" class=\"CitationRef\"\u003e62\u003c/span\u003e], evidence of effect (4 RCTs) among university students [\u003cspan citationid=\"CR63\" class=\"CitationRef\"\u003e63\u003c/span\u003e], and (8 RCTs) no evidence of effect [\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe three reviews with meta-analyses had various sample populations. One SR (4 RCTs) focused on social isolation and showed a considerably heterogeneous (\u003cem\u003eI\u003c/em\u003e\u003csup\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;79%) moderate effect (g -0.67 [-0.98; -0.36]) [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Three SRs (6‒15 RCTs) reported on loneliness, and all showed substantial heterogeneity in the effects (\u003cem\u003eI\u003c/em\u003e\u003csup\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sup\u003e\u0026thinsp;\u0026ge;\u0026thinsp;60%). Two of the SRs found no evidence of effect [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e], and one found a small effect (SMD \u0026minus;\u0026thinsp;0.30 [-0.50; -0.09]) [\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e]. None of the SRs addressed long-term effects.\u003c/p\u003e \u003cp\u003e[Insert Table \u003cspan refid=\"Tab10\" class=\"InternalRef\"\u003e4\u003c/span\u003eb/5b about here]\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003eSocial support interventions\u003c/h2\u003e \u003cp\u003eSocial support interventions were primarily befriending efforts delivered individually. Typically, these interventions were facilitated by a volunteer and scheduled on a weekly or bi-weekly basis spanning up to one year. The mode of delivery varied, taking place either in-person or through digital platforms [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e, \u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eSix meta-analyses and two narrative syntheses reported on social support interventions (Table\u0026nbsp;\u003cspan refid=\"Tab10\" class=\"InternalRef\"\u003e4\u003c/span\u003ec and Table\u0026nbsp;\u003cspan refid=\"Tab17\" class=\"InternalRef\"\u003e5\u003c/span\u003ec). As the narrative syntheses [\u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e61\u003c/span\u003e, \u003cspan citationid=\"CR63\" class=\"CitationRef\"\u003e63\u003c/span\u003e] incorporated only 1\u0026ndash;2 RCTs (n\u0026thinsp;=\u0026thinsp;171\u0026thinsp;\u0026minus;\u0026thinsp;331) for each outcome, the conclusions drawn regarding the effects remain uncertain. Only one SR with meta-analysis (4 RCTs) focused on social isolation, showing a small non-significant effect (g 0.29 [-0.09; 0.67], \u003cem\u003eI\u003c/em\u003e\u003csup\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;49%) within mixed populations [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eSix SRs with meta-analysis addressed loneliness, of which two focused on populations of all ages based on 10 [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e] and 22 [\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e] RCTs, one on younger people (4 RCTs) [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e], and three on older adults (3\u0026ndash;5 RCTs) [\u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e, \u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e, \u003cspan citationid=\"CR64\" class=\"CitationRef\"\u003e64\u003c/span\u003e]. The effects were inconsistent with four SRs showing no evidence of effects and two reporting small-moderate effects that were moderately to substantially heterogeneous (SMD \u0026minus;\u0026thinsp;0.39 [-0.56; -0.23], \u003cem\u003eI\u003c/em\u003e\u003csup\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sup\u003e\u0026thinsp;\u0026ge;\u0026thinsp;65% [\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e]; SMD \u0026minus;\u0026thinsp;0.47 [-0.77; -0.18], \u003cem\u003eI\u003c/em\u003e\u003csup\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;42% [\u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e]).\u003c/p\u003e \u003cp\u003e[Insert Table \u003cspan refid=\"Tab10\" class=\"InternalRef\"\u003e4\u003c/span\u003ec/5c about here]\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003ePsychological interventions\u003c/h2\u003e \u003cp\u003ePsychological interventions most frequently involve cognitive-behavioral therapy (CBT) and mindfulness-based stress-reduction [\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e, \u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e65\u003c/span\u003e]. A few used reminiscence therapy for older adults and animal-assisted therapy, where participants interacted with either live dogs or robotic animals such as seals or dogs [\u003cspan citationid=\"CR66\" class=\"CitationRef\"\u003e66\u003c/span\u003e]. Most interventions were delivered individually, with some opting for group settings. These were more often delivered face-to-face than digitally, according to the SRs providing such details [e.g., 32, 49, 56]. The frequency and duration of interventions varied as well, typically occurring weekly or biweekly, with durations ranging from a few weeks to up to a year. Follow-up effects were largely unaddressed.\u003c/p\u003e \u003cp\u003eBased on 15 SRs (some with multiple analyses for different subgroups), the evidence on psychological interventions included 10 meta-analyses and 9 narrative syntheses (Table\u0026nbsp;\u003cspan refid=\"Tab10\" class=\"InternalRef\"\u003e4\u003c/span\u003ed and \u003cspan refid=\"Tab17\" class=\"InternalRef\"\u003e5\u003c/span\u003ed). Population groups varied widely across reviews, with five addressing a mixed population [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e, \u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e, \u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e55\u003c/span\u003e, \u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e61\u003c/span\u003e], three targeting younger people [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e, \u003cspan citationid=\"CR63\" class=\"CitationRef\"\u003e63\u003c/span\u003e, \u003cspan citationid=\"CR67\" class=\"CitationRef\"\u003e67\u003c/span\u003e], five targeting older adults [\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e, \u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e, \u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e, \u003cspan citationid=\"CR66\" class=\"CitationRef\"\u003e66\u003c/span\u003e, \u003cspan citationid=\"CR68\" class=\"CitationRef\"\u003e68\u003c/span\u003e], and two focusing on people with mental health concerns [\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e, \u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e59\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eFour SRs focused on social isolation, all employing narrative synthesis [\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e, \u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e, \u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e59\u003c/span\u003e, \u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e61\u003c/span\u003e]. Based on 4 RCTs, these reviews presented inconclusive or no evidence of effects. Among the eight reviews with narrative syntheses on loneliness, conclusions were also mixed and based on few (2\u0026thinsp;\u0026minus;\u0026thinsp;7) RCTs. Some of the evidence showed effect, among university students [\u003cspan citationid=\"CR63\" class=\"CitationRef\"\u003e63\u003c/span\u003e] or older adults in long-term care [\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e, \u003cspan citationid=\"CR68\" class=\"CitationRef\"\u003e68\u003c/span\u003e]. Others reported inconclusive evidence, in mixed populations [\u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e61\u003c/span\u003e], among people with mental health issues [\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e, \u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e59\u003c/span\u003e], young adults [\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e, \u003cspan citationid=\"CR67\" class=\"CitationRef\"\u003e67\u003c/span\u003e, \u003cspan citationid=\"CR68\" class=\"CitationRef\"\u003e68\u003c/span\u003e], and older adults [\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e, \u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e61\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eOf the 10 SRs with meta-analyses on the effect of psychological interventions to reduce loneliness, seven showed benefits [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e, \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e, \u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e, \u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e, \u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e55\u003c/span\u003e, \u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e]. Three SRs based on few (2\u0026thinsp;\u0026minus;\u0026thinsp;4) RCTs reported small to moderate effects that were not significant [\u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e, \u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e55\u003c/span\u003e, \u003cspan citationid=\"CR66\" class=\"CitationRef\"\u003e66\u003c/span\u003e]. The seven showing effects included up to 31 RCTs and the effects were generally moderate-large in size and substantially to considerably heterogeneous (\u003cem\u003eI\u003c/em\u003e\u003csup\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sup\u003e\u0026thinsp;\u0026ge;\u0026thinsp;65%). For example, the SR of 31 RCTs found a moderate effect (SMD 0.43 [0.18; 0.68, \u003cem\u003eI\u003c/em\u003e\u003csup\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;90%) [\u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e]. The power of the meta-analyses is crucial as despite the pooled analyses showing significant effects, approximately half of their constituent RCTs did not [see 32, 55, 66, 69]. Two SRs reported a GRADE certainty of the evidence; the resulting grades were 'low' [\u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e55\u003c/span\u003e] and 'moderate' [\u003cspan citationid=\"CR70\" class=\"CitationRef\"\u003e70\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e[Insert Table \u003cspan refid=\"Tab10\" class=\"InternalRef\"\u003e4\u003c/span\u003ed/5d about here]\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003ePsychoeducation interventions\u003c/h2\u003e \u003cp\u003ePsychoeducation interventions typically involved educating individuals at risk of loneliness (e.g., due to mental health issues) about topics relevant to loneliness or health more generally (Tables\u0026nbsp;\u003cspan refid=\"Tab10\" class=\"InternalRef\"\u003e4\u003c/span\u003ee and \u003cspan refid=\"Tab17\" class=\"InternalRef\"\u003e5\u003c/span\u003ee). These interventions were addressed in two meta-analyses [\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e, \u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e] and four narrative syntheses [\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e, \u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e59\u003c/span\u003e, \u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e61\u003c/span\u003e, \u003cspan citationid=\"CR63\" class=\"CitationRef\"\u003e63\u003c/span\u003e]. Three SRs did not report population details, and others focused on younger people [\u003cspan citationid=\"CR63\" class=\"CitationRef\"\u003e63\u003c/span\u003e], older adults [\u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e], or people with mental health problems [\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e, \u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e59\u003c/span\u003e]. The narrative syntheses reported inconclusive evidence for benefits of psychoeducational interventions to reduced social isolation [\u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e59\u003c/span\u003e] or loneliness [\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e, \u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e59\u003c/span\u003e, \u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e61\u003c/span\u003e, \u003cspan citationid=\"CR63\" class=\"CitationRef\"\u003e63\u003c/span\u003e]. The meta-analyses on the effects of psychoeducational interventions for loneliness were reported as having a small effect (SMD \u0026minus;\u0026thinsp;0.19 [-0.35; -0.03], \u003cem\u003eI\u003c/em\u003e\u003csup\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;0%) and a large effect (SMD \u0026minus;\u0026thinsp;1.12 [-2.61; -0.36], \u003cem\u003eI\u003c/em\u003e\u003csup\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;65%), the latter with substantial heterogeneity. The SRs contained sparse additional intervention details, and none included follow-up data.\u003c/p\u003e \u003cp\u003e[Insert Table \u003cspan refid=\"Tab10\" class=\"InternalRef\"\u003e4\u003c/span\u003ee/5e about here]\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec17\" class=\"Section2\"\u003e \u003ch2\u003eSocial skills interventions\u003c/h2\u003e \u003cp\u003eSocial skills interventions were primarily delivered in-person, adopting a group format, and typically held on a weekly basis. The duration of these interventions varied, ranging from six weeks to a year. These interventions were explored in two SRs [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e, \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e] with three meta-analyses and four SRs with narrative synthesis [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e, \u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e59\u003c/span\u003e, \u003cspan citationid=\"CR67\" class=\"CitationRef\"\u003e67\u003c/span\u003e] (Tables\u0026nbsp;\u003cspan refid=\"Tab10\" class=\"InternalRef\"\u003e4\u003c/span\u003ef and \u003cspan refid=\"Tab17\" class=\"InternalRef\"\u003e5\u003c/span\u003ef). Of these, two SRs included diverse populations [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e], two focused on people with mental health issues [\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e, \u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e59\u003c/span\u003e], and two focused on younger people at risk of loneliness such as those diagnosed with Autism Spectrum Diagnosis (ASD), social phobia, or other mental health conditions [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e, \u003cspan citationid=\"CR67\" class=\"CitationRef\"\u003e67\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eTwo of the SRs focused on social isolation using narrative syntheses, each based on 2\u0026ndash;3 RCTs. One reported inconclusive outcomes [\u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e59\u003c/span\u003e], and the other reported beneficial effects [\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e]. Three other SRs with narrative synthesis focused on effects on loneliness, with two reporting inconclusive evidence (based on 2\u0026ndash;4 RCTs) [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e59\u003c/span\u003e] and one reporting effects (2 RCTs) [\u003cspan citationid=\"CR67\" class=\"CitationRef\"\u003e67\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThree meta-analyses indicated the effect of social skills interventions on loneliness. One such analysis showed a small and considerably heterogeneous effect (SMD \u0026minus;\u0026thinsp;0.38 [-0.62; -0.15], \u003cem\u003eI\u003c/em\u003e\u003csup\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sup\u003e\u0026thinsp;\u0026gt;\u0026thinsp;65%), with the GRADE certainty of evidence rated as \u0026ldquo;moderate\u0026rdquo; [\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e]. One SR on young persons performed a separate analysis for \u0026ldquo;at-risk\u0026rdquo; groups (g 0.44 [0.10; 0.79], \u003cem\u003eI\u003c/em\u003e\u003csup\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sup\u003e NR, 5 RCTs) and for children under age 15 (g 0.27 [-0.01; 0.53], \u003cem\u003eI\u003c/em\u003e\u003csup\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sup\u003e NR, 7 RCTs), demonstrating a moderate effect of social skills interventions on loneliness in the former group [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e[Insert Table \u003cspan refid=\"Tab10\" class=\"InternalRef\"\u003e4\u003c/span\u003ef/5f about here]\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec18\" class=\"Section2\"\u003e \u003ch2\u003eDigital interventions\u003c/h2\u003e \u003cp\u003eEight SRs, each based on a few (1\u0026thinsp;\u0026minus;\u0026thinsp;8) RCTs, investigated digital interventions among older adults (Tables\u0026nbsp;\u003cspan refid=\"Tab10\" class=\"InternalRef\"\u003e4\u003c/span\u003eg and \u003cspan refid=\"Tab17\" class=\"InternalRef\"\u003e5\u003c/span\u003eg). These interventions included computer training, online interaction and support, gaming, and other internet-mediated approaches. These interventions were delivered both in groups and individually, usually with 1\u0026thinsp;\u0026minus;\u0026thinsp;3 sessions per week and for a period of one to six months [\u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e, \u003cspan citationid=\"CR71\" class=\"CitationRef\"\u003e71\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eOne SR, with two narrative syntheses based on 1\u0026thinsp;\u0026minus;\u0026thinsp;2 RCTs, focused on social isolation and showed inconclusive evidence [\u003cspan citationid=\"CR72\" class=\"CitationRef\"\u003e72\u003c/span\u003e]. Four SRs with narrative synthesis focused on loneliness. These SRs demonstrated varying outcomes. No evidence of effect was found from 6 RCTs on information and communication technology (ICT) training and gaming [\u003cspan citationid=\"CR71\" class=\"CitationRef\"\u003e71\u003c/span\u003e], inconclusive evidence was found based on 1\u0026thinsp;\u0026minus;\u0026thinsp;3 RCTs evaluating online support or therapy [\u003cspan citationid=\"CR72\" class=\"CitationRef\"\u003e72\u003c/span\u003e, \u003cspan citationid=\"CR73\" class=\"CitationRef\"\u003e73\u003c/span\u003e], and evidence of effect was found on gaming and exercise (4 RCTs) [\u003cspan citationid=\"CR74\" class=\"CitationRef\"\u003e74\u003c/span\u003e]. Four SRs with meta-analysis showed no evidence of effect [\u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e, \u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e54\u003c/span\u003e, \u003cspan citationid=\"CR75\" class=\"CitationRef\"\u003e75\u003c/span\u003e, \u003cspan citationid=\"CR76\" class=\"CitationRef\"\u003e76\u003c/span\u003e], while one SR of two RCTs among individuals in long-term care showed a large and substantially heterogeneous effect (SMD \u0026minus;\u0026thinsp;1.40 [-2.37; -0.44], \u003cem\u003eI\u003c/em\u003e\u003csup\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;70%). Assessment of long-term effects was largely absent, with the exception of two SRs [\u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e54\u003c/span\u003e, \u003cspan citationid=\"CR72\" class=\"CitationRef\"\u003e72\u003c/span\u003e] that included a total of 8 RCTs, and demonstrated no evidence of effects at various time points, up to one year.\u003c/p\u003e \u003cp\u003e[Insert Table \u003cspan refid=\"Tab10\" class=\"InternalRef\"\u003e4\u003c/span\u003eg/5g about here]\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec19\" class=\"Section2\"\u003e \u003ch2\u003eOther interventions\u003c/h2\u003e \u003cp\u003eWe found five SRs that included a total of 10 analyses, including seven meta-analyses, of intervention types outside the above categories (see Appendix 8). Two SRs explored the effect of leisure and skill development, yielding inconclusive or null effects on social isolation and loneliness [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e, \u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e61\u003c/span\u003e]. One SR, adopting a narrative synthesis of two RCTs, found no effect of health and social care service interventions on loneliness [\u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e61\u003c/span\u003e]. A further SR with meta-analysis on the effects of group-based exercise interventions among older adults, found no effect on social isolation or loneliness [\u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e]. One review examined music interventions, including choir participation and music therapy, and reported a small effect on loneliness (SMD \u0026minus;\u0026thinsp;0.34 [-0.55; -0.13], 1 RCT), but no effect on social isolation (2 RCTs) [\u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e]. Two SRs evaluated interventions that combined psychotherapy and exercise. One of the reviews focused on older adults and found no evidence of effect for either social isolation or loneliness [\u003cspan citationid=\"CR77\" class=\"CitationRef\"\u003e77\u003c/span\u003e]. The other SR involving young Chinese individuals reported a large effect (SMD \u0026minus;\u0026thinsp;1.10 [-1.45; -0.71], 8 RCTs) on loneliness [\u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e65\u003c/span\u003e]. One SR assessed the effect of multicomponent interventions (various combinations) among older adults [\u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e]. In community settings, there was a small effect on social isolation (SMD 0.29 [0.15; 0.43], \u003cem\u003eI\u003c/em\u003e\u003csup\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;0%, 6 RCTs) and a moderate effect on loneliness (SMD \u0026minus;\u0026thinsp;0.67 [-1.13; -0.21], \u003cem\u003eI\u003c/em\u003e\u003csup\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sup\u003e NR, 2 RCTs), and in long-term care settings, there was a moderate effect on loneliness (SMD \u0026minus;\u0026thinsp;0.53 [-0.86; -0.20], \u003cem\u003eI\u003c/em\u003e\u003csup\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;57%, 3 RCTs).\u003c/p\u003e \u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003e The aim of the present UR was to synthesize and critically appraise systematic reviews of RCT-based evidence on the effectiveness of SIL interventions. The evidence showed that social interventions promoting social contact and providing social support are effective strategies to tackle social isolation. In contrast, psychological interventions hold the most promise for mitigating loneliness. The quality of the evidence varies greatly, and effect sizes are typically being small to moderate and displaying substantial to considerable heterogeneity. The heterogeneity can be attributed to multiple factors, including varying intervention components such as frequency, duration, setting, and content, as well as methodological limitations such as risk of bias and small sample sizes. There was no reporting that interventions did any harm, but we are uncertain whether the primary studies measured any adverse events, or if this is an oversight from SRs authors. Our overall findings confirm and strengthen the conclusions of previous URs, providing an updated and robust evidence base. We have enriched our understanding by encompassing recent evidence and by also factoring in social isolation, which mirrors the health implications of loneliness. By narrowing our focus to RCTs \u0026mdash; often hailed as the \"gold standard\" and highest level of evidence \u0026mdash; and supplementing with grey literature to potentially capture a broader scope of non-significant outcomes, we aim to fortify and elevate the overall evidence base.\u003c/p\u003e \u003cp\u003eWhy and how social interventions hold particular promise for mitigating social isolation can be offered several interpretations. Substantial evidence suggests that interventions aimed at providing social support or fostering friendships and social activity show promise in reducing social isolation, especially in the short term [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e, \u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e61\u003c/span\u003e]. However, the long-term impacts remain uncertain [\u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e59\u003c/span\u003e]. Sustainability is critical, as the immediate effect can be deemed self-evident or even tautological; the presence of social support inherently implies a reduction in social isolation\u003ca class=\"FNLink\" href=\"#Fn4\" id=\"#FNLinkFn4\"\u003e\u003c/a\u003e.\u003c/p\u003e \u003cp\u003eAlthough some well-powered meta-analyses with many RCTs and participants show small positive impacts of social interventions also on loneliness, the overall evidence shows no or inconsistent effects, suggesting a lesser and more uncertain impact on loneliness. This uncertainty suggests that increasing social contact does not necessarily alleviate loneliness unless accompanied by psychological changes [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Issues such as mistrust, negative self-beliefs, hypersensitivity to social threat and rejection, and social anxiety often intertwine with or underpin loneliness [\u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e59\u003c/span\u003e], hindering the formation and maintenance of close social relationships. For some, new social situations might bring discomfort and self-consciousness, potentially intensifying feelings of isolation rather than mitigating loneliness. Likewise, while compassionate social support and companion resources in befriending interventions can yield significant anticipatory and experienced rewards for some, as qualitative studies indicate [\u003cspan citationid=\"CR64\" class=\"CitationRef\"\u003e64\u003c/span\u003e, \u003cspan citationid=\"CR78\" class=\"CitationRef\"\u003e78\u003c/span\u003e], for others, it may highlight, stigmatize, and patronize their loneliness, exacerbating rather than reducing it. These ideas suggest that merging social interventions with psychological elements can enhance efficacy, addressing psychological issues while nurturing social relationships in a safe environment [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e, \u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e61\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eWhy and how psychological and educational interventions show more potential for reducing loneliness than social isolation can be interpreted in various ways. The moderate to large positive effects often exhibited for psychological interventions on loneliness may reflect that they address the cognitive-behavioral underlying roots of loneliness. Psychological-educational interventions address some of the same barriers and components, focusing on providing lessons on making friends and addressing barriers to social integration [\u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e]. Part of the success may also stem from the fact that the interventions target cognitive biases and avoidance behavior that underlie not only loneliness, but also mental health problems that co-exist with or underpin loneliness, such as depressive mood, anxiety, low self-worth, and social withdrawal [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Hence, the effect may be indirect by targeting the barriers to secure social connection. Their success likely also stems from being directed mainly or exclusively toward individuals who are either lonely or at risk of loneliness due to underlying psychological issues or conditions (e.g., ASD).\u003c/p\u003e \u003cp\u003eThe evidence for the effects from other types of interventions was small and inconsistent. For instance, the few SRs centered on physical activities, learning new hobbies, and health and social care services reported no evidence of effect. Digital interventions have increased in popularity in recent years and may help people stay connected with family and friends and access information or receive social support in online communities. To date, the evidence on their effectiveness for addressing SIL is uncertain. This uncertainty could reflect the highly diverse nature of digital interventions, and the fact that they have targeted older adults. While older adults are becoming more adept with technology and online communication, a significant portion may still face challenges navigating these platforms and might find such communication unsatisfying [\u003cspan citationid=\"CR79\" class=\"CitationRef\"\u003e79\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eModeration effects and subgroup heterogeneity were examined in mixed types of interventions. Only a few SRs examined longer-term effects and the results were inconsistent. For example, while one SR demonstrated that long-term effects (i.e., one to six months after the intervention) were comparable to the short-term effects (i.e., up to four weeks after the intervention) [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e], another SR found evidence of effect for up to 6 months but not thereafter [\u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e]. Furthermore, no difference in the overall effectiveness was shown for group vs. individual settings [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e, \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e, \u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e, \u003cspan citationid=\"CR60\" class=\"CitationRef\"\u003e60\u003c/span\u003e], between digital and non-digital interventions [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e, \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e], between studies of high, moderate and low quality [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e, \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e], or depending on age groups [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e, \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e] or gender [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]. The relative similarity of effects across subgroups implies that various approaches and strategies can be employed to reduce loneliness without a significant difference in outcomes.\u003c/p\u003e \u003cp\u003eThe overlap of primary studies in the results can introduce redundancy and potentially skew findings. However, in the current overview, the impact appears to be minimal due to the low degree of overlap, ensuring that the results remain predominantly independent.\u003c/p\u003e \u003cdiv id=\"Sec21\" class=\"Section2\"\u003e \u003ch2\u003eLimitations of the research evidence and implications for future research\u003c/h2\u003e \u003cp\u003eThis UR reveals several gaps and limitations in the literature, indicating areas for future research and interventions. For instance, studies need to assess interventions for young people, the persistence of intervention effects, and social isolation, which parallels loneliness in health impacts. Furthermore, there is a pressing need to evaluate broader structural determinants and interventions of SIL [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR80\" class=\"CitationRef\"\u003e80\u003c/span\u003e], using observational studies or natural experiments, because RCTs may be unsuitable for these approaches. Their absence in our UR could stem from our focus on RCTs, but notably, no structural interventions were found during our broad screening across all study designs.\u003c/p\u003e \u003cp\u003eFurthermore, trials often lack clear theoretical bases, hindering the identification of active elements that reduce loneliness. For instance, in mindfulness-based therapies, the effective factor is unclear and could be meditation, breath-work, presence, group interaction, or increased thought awareness. Similarly, it is often unclear whether interventions target lonely individuals or those presumed at risk [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e, \u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e, \u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e], requiring more clarity in future intervention design and evaluation [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e Another limitation we encountered is the quality of the trials and systematic reviews. Many trials lack adequate blinding procedures, randomization processes, and power, increasing the risk of type-I error. Furthermore, the quality of SRs is often low. Many reviews fail to preregister protocols, to use scientific quality appropriately in formulating conclusions, to specify interventions in adequate detail, and to use clear categories of interventions. These problems partly reflect the lack of detail reported in the primary studies. Meta-analysis on pooled data of highly diverse types of interventions is also problematic, as evidenced by the substantial heterogeneity of their effects. Such an approach also curtails the applicability of the results for practical purposes. Additionally, narrative synthesis within the SRs relied excessively on p-values, whereas reporting numerical data, effect sizes, and precision are preferable [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. Furthermore, combining dissimilar interventions in meta-analyses compromises the practical relevance of the pooled estimates due to the diversity of interventions [\u003cspan citationid=\"CR81\" class=\"CitationRef\"\u003e81\u003c/span\u003e]. Although some SRs include subgroup analyses, the lack of differentiation by intervention types limits the practical application of the acquired knowledge [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eBeyond structural interventions, other types of interventions also seem largely unexplored. For example, it is worth noting the potency of giving support to address one\u0026rsquo;s own social disconnection. Positive psychology interventions have long recognized that giving (generosity, prosociality) is often more powerful than receiving, challenging the assumption that people must always be on the receiving end of an intervention to address SIL. Volunteering and digital interventions, through group interactions and online forums, offer unique and flexible opportunities for reciprocal support, fostering meaningful connections and positive relationships.\u003c/p\u003e \u003cp\u003eIntegrating elements from different approaches to treat individuals holistically and individually is another avenue for future research. Given the heterogeneity of the population of lonely people, it is essential to tailor interventions to different types of loneliness, triggers, and risk groups [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e, \u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e]. For instance, those whose loneliness is rooted in insecure attachment or mental health issues might need interventions focusing on cognitive and other barriers. On the other hand, people with situational loneliness may benefit from interventions aimed at enhancing social networks and connectedness. In response to the question of common misconceptions about ways to enhance happiness, bestselling author Gretchen Rubin asserted that the fundamental mistake people make is to believe that there is a single, universally effective method [\u003cspan citationid=\"CR82\" class=\"CitationRef\"\u003e82\u003c/span\u003e]. She emphasized that happiness-enhancing strategies are profoundly individualistic, contingent on one's unique nature, interests, values, and idiosyncrasies. This perspective mirrors our own and others\u0026rsquo; [e.g., 10, 60] notions regarding mitigating SIL, dispelling the idea of a one-size-fits-all solution and instead advocating for tailored and individual-centric strategies. In the rapidly evolving digital era, the exploration of ways to improve technology-based interventions for social isolation and loneliness becomes increasingly vital.\u003c/p\u003e \u003cp\u003eBalancing these limitations were several strengths, including the use of rigorous methods and quality assessment, grouping SRs by type of intervention and outcome, the exclusive focus on RCTs, and the broad search strategy including grey literature to contribute valuable insights to the field and inform future research and practice in addressing social isolation and loneliness.\u003c/p\u003e \u003c/div\u003e"},{"header":"CONCLUSION","content":"\u003cp\u003eThere is an urgent need to develop a comprehensive, evidence-based understanding and effective remedies for SIL. However, the current evidence from SRs does not yet clearly support any specific intervention to reduce SIL. Potential interventions such as cognitive modification for loneliness and support and facilitated socialization for social isolation show promise, but the quality of published trials and SRs limits our confidence in their findings and our ability to draw firm conclusions. Compounding this uncertainty is the inconsistency within the findings, paired with our limited insight regarding the exact 'active ingredients' that bring about successful results, the interventions\u0026rsquo; relevance to different subgroups, and the circumstances under which they perform optimally. We suggest that high-quality research and innovation in intervention development informed by the limitations identified in this UR should be prioritized. Critically, the customization of interventions based on the specific type and underlying cause of loneliness appears to be crucial for the development of efficacious strategies. Incorporating elements from various approaches\u0026mdash;such as therapeutic counseling and social interaction\u0026mdash;may offer a more holistic and effective solution. Digital platforms could serve as a valuable facilitator for these tailored interventions, enabling easier implementation and potentially reaching a wider audience.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eConflict of interest\u003c/h2\u003e \u003cp\u003eThe authors declare no conflict of interest.\u003c/p\u003e \u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eRohde N, D\u0026rsquo;Ambrosio C, Tang KK, Rao P. Estimating the mental health effects of social isolation. Applied Research in Quality of Life 2016, 11(3):853\u0026ndash;869.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHawkley LC, Cacioppo JT. Loneliness matters. A theoretical and empirical review of consequences and mechanisms. 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Journal of Medical Internet Research 2018, 20(6):e10486.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHao X, Qin Y, Lv M, Zhao X, Wu S, Li K: Effectiveness of telehealth interventions on psychological outcomes and quality of life in community adults during the COVID-19 pandemic: A systematic review and meta-analysis. International Journal of Mental Health Nursing.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJin W, Liu Y, Yuan S, Bai R, Li X, Bai Z. The effectiveness of technology-based interventions for reducing loneliness in older adults: A systematic review and meta-analysis of randomized controlled trials. Frontiers in Psychology 2021, 12.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eShvedko A, Whittaker AC, Thompson JL, Greig CA. Physical activity interventions for treatment of social isolation, loneliness or low social support in older adults: A systematic review and meta-analysis of randomised controlled trials. Psychology of Sport and Exercise 2018, 34:128\u0026ndash;137.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePreston C, Moore S. Ringing the changes: the role of telephone communication in a helpline and befriending service targeting loneliness in older people. Ageing \u0026amp; Society 2019, 39(7):1528\u0026ndash;1551.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOh SS, Kim K-A, Kim M, Oh J, Chu SH, Choi J. Measurement of digital literacy among older adults: systematic review. Journal of Medical Internet Research 2021, 23(2):e26145.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePitman A, Mann F, Johnson S. Advancing our understanding of loneliness and mental health problems in young people. The Lancet Psychiatry 2018, 5(12):955\u0026ndash;956.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBorenstein M, Hedges LV, Higgins JP, Rothstein HR. Introduction to meta-analysis: John Wiley \u0026amp; Sons; 2021.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRubin G. \u0026ldquo;The Happiness Lab by Laurie Santos\u0026rdquo; podcast. 29 May 2023.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Footnotes","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003e Clearly defined inclusion criteria regarding population, type of intervention, and outcomes. We did not require a clearly defined comparator, given their highly diverse nature in this field.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003e The form we created for data extraction included explanations for each item and their categories. We piloted the form with two systematic reviews to ensure authors consistently extracted the same data using the same categories for the variables of interest.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003e Three SRs (10, 32, 47) express reductions in SIL with positively valanced effect sizes.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003e Social interventions spanned a few weeks to a maximum of one year in duration. However, data on long-term effects and post-intervention follow-ups was largely unavailable.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Tables 3-5","content":"\u003cp\u003eTables 3-5 are available in the Supplementary Files section.\u003c/p\u003e"},{"header":"Appendices","content":"\u003cp\u003eAppendices 1-8 are not available with this version.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-3351098/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-3351098/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eSocial isolation and loneliness are urgent public health concerns associated with negative physical and mental health outcomes. Understanding effective remedies is crucial in addressing these problems.\u003c/p\u003e\u003ch2\u003eObjectives\u003c/h2\u003e \u003cp\u003eTo synthesize and critically appraise scientific evidence on the effectiveness of social isolation and loneliness interventions overall and across subgroups. We focused on systematic reviews (SRs) of randomized controlled trials (RCTs).\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eWe searched seven databases (June 2022 and updated June 2023) and supplemented the search with grey literature and reference screening to identify SRs published since 2017. Screening, data extraction, and quality assessment using the AMSTAR2 tool were conducted independently by author pairs, with disagreements resolved through discussion.\u003c/p\u003e\u003ch2\u003eFindings:\u003c/h2\u003e \u003cp\u003eWe included 29 SRs, 16 with meta-analysis and 13 with narrative synthesis. All SRs focused on loneliness, with 12 additionally examining social isolation. Four SRs focused on young people, 11 on all ages, and 14 on older adults. The most frequently examined intervention types were social (social contact, social support), psychological (therapy, psychoeducation, social skills training), and digital (e.g., computer use and online support). Meta-analyses indicated small-to-moderate beneficial effects, while narrative synthesis demonstrated mixed or no effect. Social interventions for social isolation and psychological interventions for loneliness were the most promising. However, caution is warranted due to the effects\u0026rsquo; small magnitude, significant heterogeneity, and the variable quality of SRs. Digital and other interventions showed mixed or no effect; however, caution is advised in interpreting these results due to the highly diverse nature of the interventions studied.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eThis overview of SRs shows small to moderate effectiveness of social interventions in reducing social isolation and psychological ones in tackling loneliness. Further rigorously conducted RCTs and SRs are needed to guide policy decisions regarding the implementation of efficacious and scalable interventions. Evaluation should focus on both preventive structural interventions and tailored mitigating strategies that address specific types and causes of loneliness.\u003c/p\u003e","manuscriptTitle":"Tackling social disconnection: An umbrella review of RCT-based interventions targeting social isolation and loneliness","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2023-09-15 17:48:17","doi":"10.21203/rs.3.rs-3351098/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"464948eb-6e90-49e9-9a63-698af7be1fde","owner":[],"postedDate":"September 15th, 2023","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":24585576,"name":"Psychology"}],"tags":[],"updatedAt":"2023-09-15T17:48:17+00:00","versionOfRecord":[],"versionCreatedAt":"2023-09-15 17:48:17","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-3351098","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-3351098","identity":"rs-3351098","version":["v1"]},"buildId":"7rjqhiLT3MXkJMwkYKINL","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}