Effect of Cognitive Behavioral Social Skills Training on Functioning in Schizophrenia: Protocol for an Individual Participant Data Meta-Analysis of Randomized Controlled Trials

Effect of Cognitive Behavioral Social Skills Training on Functioning in Schizophrenia: Protocol for an Individual Participant Data Meta-Analysis of Randomized Controlled Trials | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Effect of Cognitive Behavioral Social Skills Training on Functioning in Schizophrenia: Protocol for an Individual Participant Data Meta-Analysis of Randomized Controlled Trials Matthias Pillny, Jason Holden, Dan Devoe, Peter Link, Eric Granholm This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5377914/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 05 Mar, 2026 Read the published version in Systematic Reviews → Version 1 posted 5 You are reading this latest preprint version Abstract Background Cognitive Behavioral Social Skills Training (CBSST) is a targeted psychological intervention designed to improve daily functioning and to address negative symptoms in individuals diagnosed with schizophrenia. Despite evidence from clinical trials suggesting beneficial effects of CBSST on functioning and negative symptoms, the overall efficacy of CBSST remains to be quantified. Furthermore, potential moderators and mediators of treatment outcomes remain elusive. This protocol outlines an Individual Participant Data Meta-Analysis (IPD-MA) with the objective to examine the efficacy of CBSST on psychosocial functioning in schizophrenia. Methods In accordance with the Preferred Reporting Items for a Systematic Review and Meta-analysis of Individual Participant Data (PRISMA-IPD) guidelines, we will conduct a systematic literature search and employ two-stage and one-stage meta-analytical approaches to ensure robust data synthesis. The meta-analytical models will evaluate the overall effect of CBSST relative to control treatments in randomized controlled trials, identify participant-level (e.g., age, cognitive impairment) and study-level (e.g., individual vs. group settings) predictors of change, and explore the mechanisms that mediate improvement in functioning, such as skills acquisition and cognitive restructuring of defeatist attitudes. Furthermore, the analysis will attempt to determine the optimal amount of CBSST sessions required to enhance functioning and evaluate the impact of patient-level factors driving delivered dosage. Discussion The objective of this study is to contribute to the existing literature by addressing the current gaps in understanding the efficacy of CBSST and identifying critical factors for treatment success. Our findings will have the potential to inform personalized treatment planning and the development of clinical guideline recommendations focusing on functional outcomes and negative symptoms in people with schizophrenia. Registration: submitted October 23rd, 2024 (605353) Schizophrenia CBSST functioning social recovery negative symptoms evidence-based psychotherapy psychosis amotivation defeatist beliefs social skills Introduction Schizophrenia is a complex and debilitating mental disorder characterized by a range of cognitive, emotional, and social dysfunctions that are associated with the decline in an individual's daily-life functioning. The negative symptoms of schizophrenia (i.e., avolition, anhedonia, asociatlity, blunted affect and alogia; 1) account for much of the variance in poor functioning outcomes (e.g., 2) and are a largely unmet treatment need. Antipsychotic medication is suspected to impede long-term functioning (3), while the evidence-base for psychological interventions is modest with small and short-term effect sizes on negative symptoms (4). Consequently, despite advances in psychological treatment of delusions and hallucinations (Garety et al., in press; 5), at least 50% of individuals with schizophrenia continue to experience pronounced negative symptoms and consequently significant impairments in everyday skills that are required for independent living, such as their ability to maintain relationships, engage in employment, and navigate everyday challenges (6-8). Cognitive Behavioral Social Skills Training (CBSST; 9) has emerged as a promising evidence-based intervention. It combines cognitive-behavioral techniques with social skills training to address the cognitive and social deficits that are common in schizophrenia and have been shown to be associated with negative symptoms and functional impairment (10-17). CBSST therefore emphasizes the importance of skill acquisition and incorporates elements of cognitive restructuring to challenge dysfunctional thinking patterns that impede social engagement (e.g., 18, 19). Thus, by fostering social interaction and general problem-solving abilities and addressing the cognitive barriers to effective communication and pursuit of recovery goals, CBSST offers a multifaceted targeted approach to improving psychosocial functioning in individuals with schizophrenia-spectrum disorders. Prior randomized-control trials (RCTs) have demonstrated that, compared to treatment as usual or goal-focused supportive contact, CBSST is effective at improving functioning and, in clinical trials with non-geriatric samples, was effective at improving amotivation, asociality, and anhedonia domains of negative symptoms in people with schizophrenia at post-treatment and up to 1-year follow-up (20-24). Moreover, studies investigating mechanisms of change in CBSST have found that significant reductions in defeatist performance beliefs mediated improvement in experiential negative symptoms and functioning and participants with more severe defeatist beliefs prior to treatment showed better outcome in CBSST (20, 21, 25). While these findings suggest that - at the study level - CBSST is effective in improving psychosocial functioning and in alleviating experiential negative symptoms and defeatist beliefs, a comprehensive meta-analytic aggregation of the available evidence is currently lacking. Previous meta-analyses investigating the effects of psychological interventions in general on functioning outcomes in patients with schizophrenia have included only a subset of the available evidence on CBSST, which might have led to an incomplete understanding of the true efficacy of CBSST (e.g., 26). Furthermore, previous evidence indicates that CBSST may have varying effects on specific populations, including middle-aged or older patients (20, 22), those with particularly pronounced deficits in executive function (27) and more severe defeatist attitudes and negative symptoms (23, 28). For instance, male patients have more prevalent negative symptoms and social functional impairment compared to other genders (29-31). Thus, a more nuanced understanding of the efficacy of CBSST could be achieved by investigating potential participant-level moderators of treatment effects across different studies. This could facilitate an improved understanding of the underlying mechanisms of change and contribute to the development of differential indications and personalized treatment approaches. However, classical meta-analyses are unable to account for the complexity and heterogeneity of CBSST's effects at the participant level. This is due to the fact that these focus on synthesizing overall treatment effects across studies by aggregating average effect sizes at the study level. This ‘study-level approach’ does not account for variation in participant-level characteristics and may obscure interactions between participant characteristics and treatment outcomes. An individual participant data (IPD) meta-analysis allows us to analyze raw data collected from individual studies and enables the examination of participant-level predictors that traditional aggregate meta-analyses do not readily account for (32). Moreover, this approach enhances statistical power by leveraging larger, pooled data sets, allowing for more precise analyses of treatment effects based on varying patient-level characteristics and can yield more reliable and robust conclusions (33). Thus, a comprehensive IPD meta-analysis of CBSST will bridge the gap of knowledge on the overall efficacy of CBSST on functioning as well as on study- and participant-level predictors of change. The aim of this study is to synthesize existing evidence through an Individual Participant Data Meta-Analysis (IPD-MA) by (1) evaluating the overall efficacy of CBSST on social functioning outcomes in people with schizophrenia, (2) identifying patient-level (e.g., age, gender, cognitive functioning, defeatist attitudes, etc.) and study-level (e.g., blended digital intervention, group vs. individual format, active vs. passive comparator, etc.) predictors of treatment efficacy, (3) exploring the mechanisms of change, such as level of skill learning and change in cognitive attitudes, in facilitating improvements in functioning and (4) to determine the dose of CBSST (number of sessions) needed to improve functioning and whether dosage is impacted by patient-level predictors (e.g., age, cognitive impairment, etc.). Our main hypothesis is that CBSST will be superior to control condition in improving functioning and secondary outcomes. Method Methods for this IPD-MA are based on the Preferred Reporting Items for a Systematic Review and Meta-analysis of Individual Participant Data ( 34 ). The protocol has been submitted to PROSPERO on October 23rd, 2024 (605353). We will update the record with any changes that will be made to the original protocol. Eligibility Criteria Participants We will include participants (as defined in the original studies) with the diagnosis of a schizophrenia-spectrum disorder (i.e., Schizophrenia, schizoaffective disorder, schizophreniform disorder, etc.) according to ICD-9, ICD-10, DSM IV or DSM 5. All kinds of diagnostic procedures and all kinds of comorbid disorders will be accepted. Populations with subthreshold psychotic symptoms (e.g., clinical high-risk populations or attenuated psychosis syndrome) will be excluded. There will be no restrictions regarding demographics (e.g., age, gender, race, etc.). Intervention Cognitive Behavioral Social Skills Training (CBSST) is an evidence-based psychosocial treatment designed for individuals with schizophrenia and other schizophrenia-spectrum disorders ( 9 ). It integrates cognitive behavioral therapy techniques with social skills training to address both the cognitive and social functioning deficits common in schizophrenia. CBSST is typically delivered in group sessions, allowing for peer support, observation of social interactions, and skill practice in a safe environment. Groups usually meet weekly over several months but other formats such as individual sessions delivered on Assertive Community Treatments teams ( 35 ) have also been tested. Moreover, other trials have combined forms of CBSST with nasal administration of Oxytocin ( 36 ), compensatory cognitive training ( 23 , 28 ) or mobile digital interventions ( 37 , 38 ). In the original manual, three modules focus on specific skill sets, including recognizing and changing dysfunctional thoughts and beliefs, improving social communication skills, and solving everyday problems related to recovery goal achievement. The techniques involve a mix of psychoeducation, skills training, and practical exercises. Specifically, the three CBSST modules are: The Cognitive Skills Module encourages participants to recognize and challenge defeatist thoughts that can impede the motivation to engage in social situations or work on recovery goals. It is foundational, as the techniques taught are integrated throughout the other two modules. Core principles include psychoeducation about the generic cognitive model (i.e., the link between thoughts, feelings, and behavior), about automatic thoughts, and common mistakes in thinking such as overly pessimistic expectations (e.g., “I won’t like it”) and defeatist beliefs (e.g., “I can’t succeed”). Techniques that are trained to challenge these thoughts include behavioral experiments, and mnemonic aids (e.g., “The 3C’s: Catch it, Check it, Change it” for challenging thoughts). The Social Skills Module aims to improve social interaction and communication skills. Participants are encouraged and guided to practice specific behaviors and techniques needed for successful social functioning in a variety of settings, such as talking to others, handling conflicts, and making requests. The key techniques include role-play exercises, behavioral rehearsal of social skills such as active listening and assertive communication and feedback-reinforcement. The Problem-Solving Skills Module aims to improve the participants’ skills in developing approaches to solving everyday problems. The goal is to equip individuals with the skills to effectively navigate challenges in their personal, social, and work lives. The mnemonic SCALE acronym ( S pecify the problem, C onsider all possible solutions, A ssess the best solution, L ay out a plan, and E xecute and evaluate the outcome) is used to teach the standard 5-steps of problem-solving. These modules are usually delivered sequentially but are integrated throughout the training to build a comprehensive skill set for managing daily life challenges and working on recovery goals. Setting a living, learning, working or socializing recovery goal, and breaking this long-term recovery goal down into short-term goals and goal steps that can be accomplished each week by using the skills in the three modules is the cornerstone of the CBSST intervention. Comparator Any kind of comparator will be included. On the study level, comparators will be classified as either passive (i.e., treatment as usual/waitlist) or active such another psychosocial intervention or supportive counseling. The comparator classification will be coded in the data and tested as a covariate of the synthesized effect of CBSST on outcomes. Study Type We will include randomized controlled trials (RCTs) that compared CBSST to a control condition, as defined above, in patients diagnosed with a schizophrenia-spectrum disorder. Studies delivering only CBT or SST, or solely online versions of CBSST interventions without personal therapeutic contacts will be excluded. Quasi-RCTs, cluster RCTs, case studies and cross-over trials will be excluded. There will be no restrictions to study context or setting. Information about context and setting will be coded in the data and tested as covariates in moderation analyses. These will include a) in- vs. outpatient settings, b) individual vs. group therapy, c) research clinic vs. other services and d) ‘classical’ CBSST vs. augmented CBSST (e.g., by compensatory cognitive training or mobile digital interventions). Outcomes The outcomes were selected and defined in consideration of the main treatment targets proposed in the CBSST manual (9) and after pilot screening of study articles. Primary Outcomes The primary outcome will be the level of functioning at the final follow-up of each included study. Eligible functioning measures are validated scales that capture a type of psychosocial functioning (i.e. an individual's ability to perform and manage daily activities, maintain social relationships, and fulfill social roles within their environment). This encompasses a wide range of skills and behaviors that allow a person to effectively interact with others, manage emotions, and cope with the demands of daily-life. Measures of global functioning, role- or social functioning will be eligible. This time-point was selected as primary because it represents the culmination of the intervention's long-term effects that are likely to evolve over time on an individual's ability to function in their daily life. By focusing on the final follow-up, we aim to capture the sustained impact of CBSST on psychosocial functioning, beyond any immediate or short-term improvements. Secondary Outcomes We will also collect data on the following secondary outcomes, if available: 1. Severity of negative symptoms a. According to the two-factor model (i.e., experiential and expressive negative symptoms; 39) b. According to the five-factor model (i.e., avolition, anhedonia, asociality, blunted affect and alogia; 1) 2. Severity of positive symptoms 3. Severity of depressive symptoms 4. Severity of defeatist performance beliefs 5. Severity of asocial beliefs 6. Cognitive functioning (global and attention/processing speed, verbal learning and memory, and executive function domains) 7. CBSST skill learning 8. Social communication skills 9. Quality of life Information sources and search strategy A systematic literature search following Preferred Reporting Items for a Systematic Review and Meta-analysis of Individual Participant Data (PRISMA-IPD; 34) will be conducted. To identify relevant records, three databases will be searched. PubMed will be searched via MEDLINE using the “.mp” field extension, which includes nine search fields (Title, Abstract, Heading Word, Table of Contents, Key Concepts, Original Title, Tests & Measures, MeSH). PsycINFO will be searched via NCBI using the “All Fields” preset. Embase will be searched using the "ALL" field command. Additionally clinical trial registries such as clinicaltrials.gov will be searched for unpublished data. For all databases, the search will be limited to records dating back to 2005, written in either English or German. The query will include a term referring to psychotic disorders and a term referring to CBSST to appear concurrently in the search fields. Manual reference section citation searches of included articles and previous review articles will be conducted. Google Scholar will be used for additional manual searches. A medical librarian will be consulted with the protocol at Universität Hamburg before searches will be conducted. Identified records will be handled using AI assisted tools such as Covidence or Rayan to remove duplicates and to perform the title and abstract screening. We will contact the authors of eligible studies and request anonymized IPD and any additional relevant studies or information. E-mails will be sent to the first and/or corresponding author of the studies. In the event of non-response, we will send reminders and attempt to contact other authors or use alternative communication methods, such as telephone. Should there be persistent uncertainty regarding the eligibility criteria and/or IPD availability due to inadequate author responses despite our efforts, the study will be excluded from the analysis. Study selection and data collection Study selection MP and DD will independently screen the records for inclusion and apply the eligibility criteria following a two-step screening process. First, titles and abstracts will be screened to identify potentially eligible studies. Second, full texts of potentially relevant or unclear records will be obtained and assessed against the eligibility criteria. Disagreements between the individual judgements will be resolved by discussion with EG and JH. When required, further information will be requested from study authors. Decisions will be recorded in a table documenting the study title, the study authors, the year of publication and the reason for exclusion. The process of study selection will be reported with a PRISMA-IPD flow diagram. Data collection and extraction MP and EG will request IPD from all selected records. PL will merge harmonized individual participant data of all included records and add a categorical trial identifier assigning each participant to the respective trial. Data will be merged into a long format file with rows by participant and study visit/ time points. An additional categorical variable will be added identifying the number of the respective study visit. Furthermore, another continuous variable will contain information about the follow-up duration from baseline in months. The final dataset will be validated by MP and JH by examining for missing values, outliers, and duplicated values, and the adequacy of randomization (if possible with the available data), and cross-check with the summary statistics reported in the published studies. In case of any discrepancies, we will collaborate with the study authors to address and resolve the issues. When IPD are not available, two independent reviewers will extract aggregated data from the original reports. Please see preregistration record for the full list of extracted variables. Risk‐of‐bias assessment Risk of bias in individual studies will be assessed by MP and DD using the Version 2 of the Cochrane risk-of-bias tool for randomized trials (RoB 2; 40). Any disagreement will be resolved by discussion with JH and EG. RoB 2 uses signaling questions and an algorithm to help make judgements of ‘low risk’, ‘some concerns’ or ‘high risk’ related to five domains: 1. Bias arising from the randomization process 2. Bias due to deviations from intended interventions 3. Bias due to missing outcome data 4. Bias in measurement of the outcome 5. Bias in selection of the reported result An overall risk of bias will be determined by the tool’s algorithm. The assessment will be done for the trial’s main outcome and with respect to the assignment to the intervention (intention-to-treat effect). These judgements will be used to inform the assessment of within-study bias in the evaluation of the confidence of the evidence (see “Confidence in the evidence”) and will be included in between-study moderator analyses to test whether the effect of CBSST is dependent on a study’s risk of bias. Assessment of applicability According to our eligibility criteria, the included RCTs are expected to provide evidence regarding both the efficacy in standardized research contexts and the effectiveness of interventions in real-world settings. To further evaluate potential issues related to applicability, two independent reviewers will employ the Rating of Included Trials on the Efficacy-Effectiveness Spectrum (RITES) tool (41). The RITES tool assesses domains such as participant characteristics, trial setting, intervention flexibility, and clinical relevance. Each domain is rated on a 5-point Likert scale, ranging from 1 ("strong emphasis on efficacy") to 5 ("strong emphasis on effectiveness") . These ratings will inform the assessment of potential indirectness in the evidence (see the “Confidence in the evidence” section). Confidence in the evidence We will evaluate the certainty of the evidence using the GRADE (Grading of Recommendations, Assessment, Development, and Evaluations; 42) approach for our main outcome, namely levels of functioning. The GRADE framework provides a systematic method for assessing the quality of evidence and the strength of recommendations. It considers factors such as risk of bias, inconsistency of results, indirectness of evidence, imprecision, and publication bias. Evidence is rated across four levels: high, moderate, low, and very low certainty. This approach ensures a transparent and structured process for evaluating how much confidence can be placed in the findings of the included studies, ultimately guiding the formulation of reliable conclusions and recommendations. Data synthesis This IPD meta-analysis will include both a two- and a one staged approach. The rationale for our statistical approach follows the recommendations for practice of individual participant data meta-analyses (43) and the PRISMA-IPD criteria (34). Effect sizes For the two-stage approach, means and standard deviations of outcomes will be transformed into standardized mean differences (SMD) (44) and corrected for overestimation using Hedge’s g (45). Positive SMDs will indicate better outcomes in participants receiving CBSST, while negative SMDs reflect outcomes favoring control conditions. Effect sizes will be presented along with 95% confidence intervals. Number needed to treat will be estimated as a secondary measure of effect for functioning outcomes. For the one-stage-approach, the standardized regression-based beta-coefficient of the treatment effect with their corresponding standard error and 95% confidence intervals will be reported as measure of effect. Synthesis approach The two-stage approach. First, we will synthesize a summary effect size of CBSST on primary functioning outcomes at the final follow-up of each study following the two-stage approach. In the first stage IPD within a trial will be analyzed to generate study-level summary effect (i.e., Hedge’s g; see next section). In the second stage the effect sizes from each trial will be aggregated across trials using conventional two-level random-effects meta-analytical methods, which accounts for between-study heterogeneity (45). Heterogeneity of effect sizes will be evaluated using the Q-statistic and I² (44, 46). All statistical analyzes within the two-stage approach will be conducted using the "metafor" package (47) implemented in RStudio. The one-stage approach. In a second step, we will follow the one-stage approach by combining all individual participant data in a single meta-analysis based on a mixed linear regression model stratified by trial. These models are particularly suitable for investigating how treatment effects vary between individuals or groups and have improved ability to detect differences between groups of participants over two-stage meta-analyses due to higher statistical power. Furthermore, the one-stage approach allows to separate group-level and individual-level variance. For this IPD meta-analysis, we will estimate mixed linear models to predict functioning and secondary outcomes across the follow-up visits of each study. The model will include group (treatment vs. control group), study visit and the interaction of both as fixed effects. If model convergence can be achieved, the random effect structure will include a random intercept by trial and another by participant. Time (i.e., study visit) will be included as random slope following the maximal-random approach for multilevel modelling (48). In case of case of non-convergence, the random effect structure will be gradually simplified until convergence is achieved. Marginal and conditional R 2 will be reported as measures of model fit. These models will be estimated using the ‘lme4’ and the ‘lmertest’ packages implemented in RStudio (49, 50). Please see Wilkinson notation below: Subgroup and meta-regression analyses We will conduct a set of study-level subgroup and meta-regression analyses within the two-stage approach. Additionally, in the one-stage approach, we will test a set of participant-level covariates using meta-regressions by pooling data from all studies and directly examining the influence of individual participant characteristics. This dual approach allows for a thorough exploration of both study- and participant-level factors. Please see below for a list of subgroup and meta-regression tests. Study-Level (Two-stage approach). Type of comparator, study setting, type of trial (efficacy vs. effectiveness), level of therapist training, additional treatment modules (e.g., digital or cognitive remediation) will be tested by estimating separate meta-regression models in the second stage of the two-stage analysis Participant-Level (One-stage approach). Diagnoses, age, gender, years of education, ethnicity/race, medication status (medicated/unmedicated), type of medication at baseline, chlorpromazine equivalent doses at baseline, depressive symptoms at baseline, positive symptoms at baseline, negative symptoms at baseline, illness status (first-episode, chronic), cognitive functioning at baseline, defeatist and asocial beliefs at baseline, psychosocial functioning at baseline, number of sessions received, therapist fidelity, and social skills at baseline will be tested as covariates and their interaction with the group by study visit effect in the one-stage models separately for each outcome and covariate. An additional exploratory model including all covariates will be estimated to determine the most relevant predictors of change. Discussion Motivational negative symptoms and the resulting functional impairment of people with schizophrenia represent highly important, yet unmet treatment targets. Cognitive Behavioral Social Skills Training is a promising evidence-based and targeted psychological intervention program that combines cognitive-behavioral techniques with social skills training to address the dysfunctional beliefs and social deficits common in schizophrenia. Despite many published clinical trials investigating the efficacy of CBSST on functioning and negative symptoms, the field currently lacks a meta-analytic aggregation of the overall effect sizes of CBSST on mental health outcomes as well as an empirically informed understanding of the relevant patient-level characteristics that might affect the effect of CBSST on the study outcomes. Insights into the overall efficacy of CBSST and relevant patient-level characteristics, would improve our understanding of the benefits that can be expected from CBSST, and could inform personalized treatment in clinical routine as well as the development of treatment guidelines for schizophrenia patients with negative symptoms and functional impairments. To fill this gap and to better inform treatment planning, this individual-participant-data meta-analysis aims to provide a fine-grained synthesis of the evidence on the comparative efficacy of CBSST in patients with schizophrenia. Moreover, we will investigate patient-level (e.g., age, cognitive impairment etc.) and study-level (e.g., additional digital intervention, group vs. individual format, active vs. passive comparator etc.) predictors of treatment efficacy, explore the mechanisms of change, such as skill learning and cognitive attitudes, in facilitating improvements in functioning and determine the dose of CBSST (number of sessions) needed to improve functioning. Our planned IPD meta-analysis is conceptualized to mitigate the limitations of previous meta-analyses that used classical aggregation approaches at the study-level and, due to differing scopes, did not include the entire available evidence on CBSST. By leveraging the advantages of integrating more detailed information from IPD we will be able to provide estimates with increased reliability, and to explore factors that may influence these outcomes on the participant-level. Thus, our study will extend the existing literature on the treatment of functional impairment in patients with schizophrenia significantly. Limitations Although an IPD meta-analysis can offer a more elaborate analysis necessary to provide more precise answers for this topic, it is more complex and time and resource intensive. A major challenge will be acquiring IPD, harmonization, and analysis of the IPD datasets. Our main goal is to harmonize these datasets into a common format, allowing a detailed synthesis of the evidence. However, decisions regarding the exact model specification and standardization of variables will need to be made post-hoc and based on the available data. This process may require trade-offs between preserving data detail and achieving harmonization, but we will make pragmatic choices that maintain scientific rigor. Lastly, it is anticipated that the majority of IPDs will originate from our work group. While this offers the advantage of high data availability, it may also be prone to certain biases, such as allegiance effects when interpreting the findings. To mitigate the risk of bias in this study, we will adhere to a rigorous open science approach, wherein we publish our hypotheses and the study protocol a priori and will make any deviations from the protocol transparent. Notwithstanding our direct access to the data of most CBSST trials, it may still not be feasible to obtain IPD for some studies or outcomes, especially for those done in other work groups. We will explore potential data availability biases and consider meta-analytic models allowing the synthesis of studies providing IPD alongside those reporting only aggregate data. Conclusion It is pivotal to identify effective interventions for the management of severe functional impairment and negative symptoms in the treatment of patients with schizophrenia. Cognitive Behavioral Social Skills Training is a targeted psychological intervention program that has been demonstrated to alleviate negative symptoms and to enhance functional outcomes in a substantial number of clinical trials. Nevertheless, a comprehensive meta-analytic synthesis of the evidence, along with explicit evidence-based recommendations, remains to be undertaken. The findings of our individual-participant-data meta-analysis will provide the insights on the efficacy and differential indications to inform treatment decision-making and guideline recommendation development. Moreover, this study will identify potential gaps in the existing literature that may warrant further investigation. The findings will be published in a peer-reviewed scientific journal and subsequently disseminated in plain language through summaries and presentations to ensure broad accessibility to facilitate implementation of evidence-based interventions in clinical practice. Abbreviations CBSST Cognitive Behavioral Social Skills Training DSM IV, DSM 5 Diagnostic and Statistical Manual of Mental Disorders, Fourth and Fifth Editions GRADE Grading of Recommendations, Assessment, Development, and Evaluations ICD 9, ICD - 10 -International Classification of Diseases, Ninth and Tenth Editions IPD Individual Participant Data IPD MA -Individual Participant Data Meta-Analysis PRISMA IPD -Preferred Reporting Items for a Systematic Review and Meta-analysis of Individual Participant Data RCTs Randomized-Control Trials RITES Rating of Included Trials on the Efficacy-Effectiveness Spectrum tool SCALE Specify the problem, Consider all possible solutions, Assess the best solution, Lay out a plan, and Execute and evaluate the outcome SMD Standardized Mean Differences ROB 2 Version 2 of the Cochrane risk-of-bias tool for randomized trials Declarations Ethics approval and consent to participate Not applicable Consent for publication Not applicable Availability of data and materials The datasets analysed during the current study are not publicly available due to data protection and confidentality of individual participant data but are available from EG upon reasonable request. Competing interests Dr. Granholm has an equity interest in Granholm Consulting, Inc., a company that may potentially benefit from the research results as he receives income from the company for CBSST workshops and consulting. The terms of this arrangement have been reviewed and approved by the University of California, San Diego, in accordance with its conflict of interest policies. Funding Matthias Pillny received financial support from The Federal Ministry of Education and Research Germany (BMBF) and the Free and Hanseatic City of Hamburg under the Excellence Strategy of the Federal and State Governments (UHH/VP3/4/425 IRF_2022_Pillny). Authors' contributions Conceptualization – MP, DD, EG. Funding Acquisition - MP. Methodology - MP. Writing – Original Draft - MP. Writing – Review & Editing – MP, DD, JH, PL, EG. Acknowledgements We would like to express our sincere gratitude to all the participants who contributed their time and effort to make these studies possible. Your commitment and willingness to share your experiences have been invaluable in advancing our understanding and improving CBSST. We deeply appreciate your trust and dedication, which have been essential in helping us pursue meaningful and impactful research. Thank you for your invaluable contribution. Author Note Correspondence concerning this article should be addressed to Dr. Matthias Pillny, Clinical Psychology and Psychotherapy, Institute of Psychology, Faculty of Psychology and Human Movement Science, Universität Hamburg, Von-Melle-Park 5, 20146 Hamburg, Germany. Email: [email protected] References Strauss GP, Ahmed AO, Young JW, Kirkpatrick B. Reconsidering the latent structure of negative symptoms in schizophrenia: A review of evidence supporting the 5 consensus domains. Schizophr Bull. 2019;45:725–9. Pillny M, Lincoln TM. Predictors of improved functioning in patients with psychosis: The role of amotivation and defeatist performance beliefs. Psychiatry Res. 2016;244:117–22. 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Ecological Momentary Assessment of social functioning in schizophrenia: impact of performance appraisals and affect on social interactions. Schizophr Res. 2013;145:120–4. Couture SM, Granholm EL, Fish SC. A path model investigation of neurocognition, theory of mind, social competence, negative symptoms and real-world functioning in schizophrenia. Schizophr Res. 2011;125:152–60. Pillny M, Krkovic K, Lincoln TM. Development of the Demotivating Beliefs Inventory and Test of the Cognitive Triad of Amotivation. Cogn Therapy Res. 2018;42:867–77. Pillny M, Schlier B, Lincoln TM. I just don't look forward to anything. How anticipatory pleasure and negative beliefs contribute to goal-directed activity in patients with negative symptoms of psychosis. Schizophr Res. 2020;222:429–36. Granholm E, Holden J, Link PC, McQuaid JR, Jeste DV. Randomized controlled trial of cognitive behavioral social skills training for older consumers with schizophrenia: Defeatist performance attitudes and functional outcome. Am J Geriatric Psychiatry. 2013;21:251–62. Granholm E, Holden J, Link PC, McQuaidm JR. Randomized clinical trial of cognitive behavioral social skills training for schizophrenia: improvement in functioning and experiential negative symptoms. J Consult Clin Psychol. 2014;82:1173–85. Granholm E, McQuaid JR, McClure FS, Auslander LA, Perivoliotis D, Pedrelli P, et al. A randomized, controlled trial of cognitive behavioral social skills training for middle-aged and older outpatients with chronic schizophrenia. Am J Psychiatry. 2005;162(3):520–9. Granholm E, Twamley EW, Mahmood Z, Keller AV, Lykins HC, Parrish EM et al. Integrated Cognitive-Behavioral Social Skills Training and Compensatory Cognitive Training for Negative Symptoms of Psychosis: Effects in a Pilot Randomized Controlled Trial. Schizophr Bull. 2021:1–12. Granholm E, McQuaid JR, McClure FS, Link PC, Perivoliotis D, Gottlieb JD, et al. Randomized controlled trial of cognitive behavioral social skills training for older people with schizophrenia: 12-month follow-up. J Clin Psychiatry. 2007;68:730–7. Granholm E, Holden J, Worley M. Improvement in negative symptoms and functioning in Cognitive-Behavioral Social Skills Training for Schizophrenia: mediation by defeatist performance attitudes and asocial beliefs. Schizophr Bull. 2018;44:653–61. Bighelli I, Wallis S, Reitmeir C, Schwermann F, Salahuddin NH, Leucht S. Effects of psychological treatments on functioning in people with Schizophrenia: a systematic review and meta-analysis of randomized controlled trials. Eur Arch Psychiatry Clin NeuroSci. 2023;273(4):779–810. Rajji TK, Mamo DC, Holden J, Granholm E, Mulsant BH. Cognitive-Behavioral Social Skills Training for patients with late-life schizophrenia and the moderating effect of executive dysfunction. Schizophr Res. 2022;239:160–7. Mahmood Z, Van Patten R, Keller AV, Lykins HC, Perivoliotis D, Granholm E, et al. Reducing negative symptoms in schizophrenia: Feasibility and acceptability of a combined cognitive-behavioral social skills training and compensatory cognitive training intervention. Psychiatry Res. 2021;295:113620. Usall J, Haro J, Ochoa S, Marquez M, Araya S. group N. Influence of gender on social outcome in schizophrenia. Acta Psychiatrica Scandinavica. 2002;106(5):337 – 42. Mueser KT, Bellack AS, Morrison RL, Wade JH. Gender, social competence, and symptomatology in schizophrenia: a longitudinal analysis. J Abnorm Psychol. 1990;99(2):138. Mueser KT, Pratt SI, Bartels SJ, Forester B, Wolfe R, Cather C. Neurocognition and social skill in older persons with schizophrenia and major mood disorders: an analysis of gender and diagnosis effects. J Neurolinguistics. 2010;23(3):297–317. Riley RD, Lambert PC, Abo-Zaid G. Meta-analysis of individual participant data: rationale, conduct, and reporting. BMJ. 2010;340:c221. Debray TPA, Moons KGM, van Valkenhoef G, Efthimiou O, Hummel N, Groenwold RHH, et al. Get real in individual participant data (IPD) meta-analysis: a review of the methodology. Res Synthesis Methods. 2015;6(4):293–309. Stewart LA, Clarke M, Rovers M, Riley RD, Simmonds M, Stewart G, et al. Preferred Reporting Items for a Systematic Review and Meta-analysis of Individual Participant Data: The PRISMA-IPD Statement. JAMA. 2015;313(16):1657–65. Granholm E, Holden JL, Sommerfeld D, Rufener C, Perivoliotis D, Mueser K, et al. Enhancing assertive community treatment with Cognitive Behavioral Social Skills Training for schizophrenia: Study protocol for a randomized controlled trial. Trials. 2015;16:438. Browne J, Harvey PD, Buchanan RW, Kelly DL, Strauss GP, Gold JM et al. A Longitudinal Examination of Real-World Sedentary Behavior in Adults with Schizophrenia-Spectrum Disorders in a Clinical Trial of Combined Oxytocin and Cognitive Behavioral Social Skills Training. Behav Sci (Basel). 2022;12(3). Granholm E, Holden J, Dwyer K, Mikhael T, Link P, Depp C. Mobile-Assisted Cognitive Behavioral Therapy for Negative Symptoms: Open Single-Arm Trial With Schizophrenia Patients. JMIR Mental Health. 2020;7:e24406. Granholm E, Holden JL, Dwyer K, Link P. Mobile-assisted cognitive-behavioral social skills training in older adults with schizophrenia. J Behav Cogn Therapy. 2020;30(1):13–21. Strauss GP, Hong LE, Gold JM, Buchanan RW, McMahon RP, Keller WR, et al. Factor structure of the brief negative symptom scale. Schizophr Res. 2012;142(1):96–8. Sterne JAC, Savović J, Page MJ, Elbers RG, Blencowe NS, Boutron I, et al. RoB 2: A revised tool for assessing risk of bias in randomised trials. BMJ. 2019;l4898:366. Wieland LS, Berman BM, Altman DG, Barth J, Bouter LM, D'Adamo CR, et al. Rating of Included Trials on the Efficacy–Effectiveness Spectrum: development of a new tool for systematic reviews. J Clin Epidemiol. 2017;84:95–104. Granholm A, Alhazzani W, Møller MH. Use of the GRADE approach in systematic reviews and guidelines. Br J Anaesth. 2019;123(5):554–9. Stewart GB, Altman DG, Askie LM, Duley L, Simmonds MC, Stewart LA. Statistical Analysis of Individual Participant Data Meta-Analyses: A Comparison of Methods and Recommendations for Practice. PLoS ONE. 2012;7(10):e46042. Hedges LV, Olkin I. Statistical methods for meta-analysis. New York: Academic; 1985. p. 369. Borenstein M, Hedges LV, Higgins JPT, Rothstein HR. Introduction to meta-analysis. West Sussex: Wiley; 2009. Higgins JPT, Thompson SG, Deeks JJ, Altman DG. Measuring inconsistency in meta-analyses. BMJ. 2003;327:557–60. Viechtbauer W. Conducting meta-analyses in R with the metafor. J Stat Softw. 2010;36:1–48. Barr DJ, Levy R, Scheepers C, Tily HJ. Random effects structure for confirmatory hypothesis testing: Keep it maximal. J Mem Lang. 2013;68:255–78. Bates Mächler. Bolker, Walker. Fitting Linear Mixed-Effects Models Using lme4. J Stat Softw. 2015;67:1–48. Kuznetsova, Brockhoff C. lmerTest Package: Tests in Linear Mixed Effects Models. J Stat Softw. 2017;82:1–26. Supplementary Files PRISMAIPDchecklist.pdf Cite Share Download PDF Status: Published Journal Publication published 05 Mar, 2026 Read the published version in Systematic Reviews → Version 1 posted Editorial decision: Major revision 05 Oct, 2025 Reviewers agreed at journal 19 Apr, 2025 Reviewers invited by journal 07 Feb, 2025 Editor assigned by journal 14 Nov, 2024 First submitted to journal 02 Nov, 2024 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. 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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-5377914","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":430615328,"identity":"9152299d-797b-45f8-900b-2c90173591a1","order_by":0,"name":"Matthias Pillny","email":"data:image/png;base64,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","orcid":"https://orcid.org/0000-0003-2395-8433","institution":"Universität Hamburg Fakultät für Psychologie und Bewegungswissenschaft: Universitat Hamburg Fakultat fur Psychologie und Bewegungswissenschaft","correspondingAuthor":true,"prefix":"","firstName":"Matthias","middleName":"","lastName":"Pillny","suffix":""},{"id":430615329,"identity":"6eecc8de-3563-4771-9f65-4720a244fc42","order_by":1,"name":"Jason Holden","email":"","orcid":"","institution":"UCSD: University of California San Diego","correspondingAuthor":false,"prefix":"","firstName":"Jason","middleName":"","lastName":"Holden","suffix":""},{"id":430615330,"identity":"50106aa3-6c54-4444-8bd4-0c591c8cd8ae","order_by":2,"name":"Dan Devoe","email":"","orcid":"","institution":"Mount Royal University","correspondingAuthor":false,"prefix":"","firstName":"Dan","middleName":"","lastName":"Devoe","suffix":""},{"id":430615331,"identity":"4b473c70-65d1-4cfc-bab5-ac9245992e35","order_by":3,"name":"Peter Link","email":"","orcid":"","institution":"UCSD: University of California San Diego","correspondingAuthor":false,"prefix":"","firstName":"Peter","middleName":"","lastName":"Link","suffix":""},{"id":430615332,"identity":"f590f8dc-7bf1-401a-9ca1-8c9b5e628fd8","order_by":4,"name":"Eric Granholm","email":"","orcid":"","institution":"UCSD: University of California San Diego","correspondingAuthor":false,"prefix":"","firstName":"Eric","middleName":"","lastName":"Granholm","suffix":""}],"badges":[],"createdAt":"2024-11-02 11:12:31","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5377914/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5377914/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s13643-026-03124-x","type":"published","date":"2026-03-05T15:57:25+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":104250707,"identity":"421ad385-e1d0-4402-bd11-890ee8bd3576","added_by":"auto","created_at":"2026-03-09 16:06:16","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":798545,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5377914/v1/58bbe67b-2796-4e6a-ba5c-d492532b9652.pdf"},{"id":79759723,"identity":"253c1c0e-951c-4ee2-9160-67cd3e4b793b","added_by":"auto","created_at":"2025-04-02 10:56:45","extension":"pdf","order_by":5,"title":"","display":"","copyAsset":false,"role":"supplement","size":166455,"visible":true,"origin":"","legend":"","description":"","filename":"PRISMAIPDchecklist.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5377914/v1/1c634a56659d142f6455a7e5.pdf"}],"financialInterests":"","formattedTitle":"Effect of Cognitive Behavioral Social Skills Training on Functioning in Schizophrenia: Protocol for an Individual Participant Data Meta-Analysis of Randomized Controlled Trials","fulltext":[{"header":"Introduction","content":"\u003cp\u003eSchizophrenia is a complex and debilitating mental disorder characterized by a range of cognitive, emotional, and social dysfunctions that are associated with the decline in an individual\u0026apos;s daily-life functioning. The negative symptoms of schizophrenia (i.e., avolition, anhedonia, asociatlity, blunted affect and alogia; 1) account for much of the variance in poor functioning outcomes (e.g., 2) and are a largely unmet treatment need. Antipsychotic medication is suspected to impede long-term functioning (3), while the evidence-base for psychological interventions is modest with small and short-term effect sizes on negative symptoms (4). Consequently, despite advances in psychological \u0026nbsp;treatment of delusions and hallucinations (Garety et al., in press; 5), at least 50% of individuals with schizophrenia continue to experience pronounced negative symptoms and consequently significant impairments in everyday skills that are required for independent living, such as their ability to maintain relationships, engage in employment, and navigate everyday challenges (6-8).\u003c/p\u003e\n\u003cp\u003eCognitive Behavioral Social Skills Training (CBSST; 9) has emerged as a promising evidence-based intervention. It combines cognitive-behavioral techniques with social skills training to address the cognitive and social deficits that are common in schizophrenia and have been shown to be associated with negative symptoms and functional impairment (10-17). CBSST therefore emphasizes the importance of skill acquisition and incorporates elements of cognitive restructuring to challenge dysfunctional thinking patterns that impede social engagement (e.g., 18, 19). Thus, by fostering social interaction and general problem-solving abilities and addressing the cognitive barriers to effective communication and pursuit of recovery goals, CBSST offers a multifaceted targeted approach to improving psychosocial functioning in individuals with schizophrenia-spectrum disorders.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003ePrior randomized-control trials (RCTs) have demonstrated that, compared to treatment as usual or goal-focused supportive contact, CBSST is effective at improving functioning and, in clinical trials with non-geriatric samples, was effective at improving amotivation, asociality, and anhedonia domains of negative symptoms in people with schizophrenia at post-treatment and up to 1-year follow-up (20-24). Moreover, studies investigating mechanisms of change in CBSST have found that significant reductions in defeatist performance beliefs mediated improvement in experiential negative symptoms and functioning and participants with more severe defeatist beliefs prior to treatment showed better outcome in CBSST (20, 21, 25).\u0026nbsp;While these findings suggest that - at the study level - CBSST is effective in improving psychosocial functioning and in alleviating experiential negative symptoms and defeatist beliefs, a comprehensive meta-analytic aggregation of the available evidence is currently lacking.\u003c/p\u003e\n\u003cp\u003ePrevious meta-analyses investigating the effects of psychological interventions in general on functioning outcomes in patients with schizophrenia have included only a subset of the available evidence on CBSST, which might have led to an incomplete understanding of the true efficacy of CBSST (e.g., 26). Furthermore, previous evidence indicates that CBSST may have varying effects on specific populations, including middle-aged or older patients (20, 22), those with particularly pronounced deficits in executive function (27) and more severe defeatist attitudes and negative symptoms (23, 28). For instance, male patients have more prevalent negative symptoms and social functional impairment compared to other genders (29-31). Thus, a more nuanced understanding of the efficacy of CBSST could be achieved by investigating potential participant-level moderators of treatment effects across different studies. This could facilitate an improved understanding of the underlying mechanisms of change and contribute to the development of differential indications and personalized treatment approaches. However, classical meta-analyses are unable to account for the complexity and heterogeneity of CBSST\u0026apos;s effects at the participant level. This is due to the fact that these focus on synthesizing overall treatment effects across studies by aggregating average effect sizes at the study level. This \u0026lsquo;study-level approach\u0026rsquo; does not account for variation in participant-level characteristics and may obscure interactions between participant characteristics and treatment outcomes.\u003c/p\u003e\n\u003cp\u003eAn individual participant data (IPD) meta-analysis allows us to analyze raw data collected from individual studies and enables the examination of participant-level predictors that traditional aggregate meta-analyses do not readily account for (32). Moreover, this approach enhances statistical power by leveraging larger, pooled data sets, allowing for more precise analyses of treatment effects based on varying patient-level characteristics and can yield more reliable and robust conclusions (33). Thus, a comprehensive IPD meta-analysis of CBSST will bridge the gap of knowledge on the overall efficacy of CBSST on functioning as well as on study- and participant-level predictors of change.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe aim of this study is to synthesize existing evidence through an Individual Participant Data Meta-Analysis (IPD-MA) by (1) evaluating \u0026nbsp;the overall efficacy of CBSST on social functioning outcomes in people with schizophrenia, (2) identifying patient-level (e.g., age, gender, cognitive functioning, defeatist attitudes, \u0026nbsp;etc.) and study-level (e.g., blended digital intervention, group vs. individual format, \u0026nbsp;active vs. passive comparator, etc.) predictors of treatment efficacy, (3) exploring the mechanisms of change, such as level of skill learning and change in cognitive attitudes, in facilitating improvements in functioning and (4) to determine the dose of CBSST (number of sessions) needed to improve functioning and whether dosage is impacted by patient-level predictors (e.g., age, cognitive impairment, etc.). Our main hypothesis is that CBSST will be superior to control condition in improving functioning and secondary outcomes.\u003c/p\u003e"},{"header":"Method","content":"\u003cp\u003eMethods for this IPD-MA are based on the Preferred Reporting Items for a Systematic Review and Meta-analysis of Individual Participant Data (\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e). The protocol has been submitted to PROSPERO on October 23rd, 2024 (605353). We will update the record with any changes that will be made to the original protocol.\u003c/p\u003e\n\u003ch3\u003eEligibility Criteria\u003c/h3\u003e\n\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eParticipants\u003c/h2\u003e \u003cp\u003eWe will include participants (as defined in the original studies) with the diagnosis of a schizophrenia-spectrum disorder (i.e., Schizophrenia, schizoaffective disorder, schizophreniform disorder, etc.) according to ICD-9, ICD-10, DSM IV or DSM 5. All kinds of diagnostic procedures and all kinds of comorbid disorders will be accepted. Populations with subthreshold psychotic symptoms (e.g., clinical high-risk populations or attenuated psychosis syndrome) will be excluded. There will be no restrictions regarding demographics (e.g., age, gender, race, etc.).\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eIntervention\u003c/h3\u003e\n\u003cp\u003eCognitive Behavioral Social Skills Training (CBSST) is an evidence-based psychosocial treatment designed for individuals with schizophrenia and other schizophrenia-spectrum disorders (\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e). It integrates cognitive behavioral therapy techniques with social skills training to address both the cognitive and social functioning deficits common in schizophrenia. CBSST is typically delivered in group sessions, allowing for peer support, observation of social interactions, and skill practice in a safe environment. Groups usually meet weekly over several months but other formats such as individual sessions delivered on Assertive Community Treatments teams (\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e) have also been tested. Moreover, other trials have combined forms of CBSST with nasal administration of Oxytocin (\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e), compensatory cognitive training (\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e, \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e) or mobile digital interventions (\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e, \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e). In the original manual, three modules focus on specific skill sets, including recognizing and changing dysfunctional thoughts and beliefs, improving social communication skills, and solving everyday problems related to recovery goal achievement. The techniques involve a mix of psychoeducation, skills training, and practical exercises. Specifically, the three CBSST modules are:\u003c/p\u003e \u003cp\u003e \u003col\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eThe Cognitive Skills Module\u003c/b\u003e encourages participants to recognize and challenge defeatist thoughts that can impede the motivation to engage in social situations or work on recovery goals. It is foundational, as the techniques taught are integrated throughout the other two modules. Core principles include psychoeducation about the generic cognitive model (i.e., the link between thoughts, feelings, and behavior), about automatic thoughts, and common mistakes in thinking such as overly pessimistic expectations (e.g., \u0026ldquo;I won\u0026rsquo;t like it\u0026rdquo;) and defeatist beliefs (e.g., \u0026ldquo;I can\u0026rsquo;t succeed\u0026rdquo;). Techniques that are trained to challenge these thoughts include behavioral experiments, and mnemonic aids (e.g., \u0026ldquo;The 3C\u0026rsquo;s: Catch it, Check it, Change it\u0026rdquo; for challenging thoughts).\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eThe Social Skills Module\u003c/b\u003e aims to improve social interaction and communication skills. Participants are encouraged and guided to practice specific behaviors and techniques needed for successful social functioning in a variety of settings, such as talking to others, handling conflicts, and making requests. The key techniques include role-play exercises, behavioral rehearsal of social skills such as active listening and assertive communication and feedback-reinforcement.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eThe Problem-Solving Skills Module\u003c/b\u003e aims to improve the participants\u0026rsquo; skills in developing approaches to solving everyday problems. The goal is to equip individuals with the skills to effectively navigate challenges in their personal, social, and work lives. The mnemonic SCALE acronym (\u003cem\u003eS\u003c/em\u003epecify the problem, \u003cem\u003eC\u003c/em\u003eonsider all possible solutions, \u003cem\u003eA\u003c/em\u003essess the best solution, \u003cem\u003eL\u003c/em\u003eay out a plan, and \u003cem\u003eE\u003c/em\u003execute and evaluate the outcome) is used to teach the standard 5-steps of problem-solving.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003c/ol\u003e \u003c/p\u003e \u003cp\u003eThese modules are usually delivered sequentially but are integrated throughout the training to build a comprehensive skill set for managing daily life challenges and working on recovery goals. Setting a living, learning, working or socializing recovery goal, and breaking this long-term recovery goal down into short-term goals and goal steps that can be accomplished each week by using the skills in the three modules is the cornerstone of the CBSST intervention.\u003c/p\u003e\n\u003ch3\u003eComparator\u003c/h3\u003e\n\u003cp\u003eAny kind of comparator will be included. On the study level, comparators will be classified as either passive (i.e., treatment as usual/waitlist) or active such another psychosocial intervention or supportive counseling. The comparator classification will be coded in the data and tested as a covariate of the synthesized effect of CBSST on outcomes.\u003c/p\u003e\n\u003ch3\u003eStudy Type\u003c/h3\u003e\n\u003cp\u003eWe will include randomized controlled trials (RCTs) that compared CBSST to a control condition, as defined above, in patients diagnosed with a schizophrenia-spectrum disorder. Studies delivering only CBT or SST, or solely online versions of CBSST interventions without personal therapeutic contacts will be excluded. Quasi-RCTs, cluster RCTs, case studies and cross-over trials will be excluded. There will be no restrictions to study context or setting. Information about context and setting will be coded in the data and tested as covariates in moderation analyses. These will include a) in- vs. outpatient settings, b) individual vs. group therapy, c) research clinic vs. other services and d) \u0026lsquo;classical\u0026rsquo; CBSST vs. augmented CBSST (e.g., by compensatory cognitive training or mobile digital interventions).\u003c/p\u003e"},{"header":"Outcomes","content":"\u003cp\u003eThe outcomes were selected and defined in consideration of the main treatment targets proposed in the CBSST manual (9) and after pilot screening of study articles. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003ePrimary Outcomes\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe primary outcome will be the level of functioning at the final follow-up of each included study. Eligible functioning measures are validated scales that capture a type of psychosocial functioning (i.e. an individual\u0026apos;s ability to perform and manage daily activities, maintain social relationships, and fulfill social roles within their environment). This encompasses a wide range of skills and behaviors that allow a person to effectively interact with others, manage emotions, and cope with the demands of daily-life. Measures of global functioning, role- or social functioning will be eligible. This time-point was selected as primary because it represents the culmination of the intervention\u0026apos;s long-term effects that are likely to evolve over time on an individual\u0026apos;s ability to function in their daily life. By focusing on the final follow-up, we aim to capture the sustained impact of CBSST on psychosocial functioning, beyond any immediate or short-term improvements.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eSecondary Outcomes\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe will also collect data on the following secondary outcomes, if available:\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e1. Severity of negative symptoms\u003c/p\u003e\n\u003cp\u003ea. According to the two-factor model (i.e., experiential and expressive negative symptoms; 39)\u003c/p\u003e\n\u003cp\u003eb. According to the five-factor model (i.e., avolition, anhedonia, asociality, blunted affect and alogia; 1)\u003c/p\u003e\n\u003cp\u003e2. Severity of positive symptoms\u003c/p\u003e\n\u003cp\u003e3. Severity of depressive symptoms\u003c/p\u003e\n\u003cp\u003e4. Severity of defeatist performance beliefs\u003c/p\u003e\n\u003cp\u003e5. Severity of asocial beliefs\u003c/p\u003e\n\u003cp\u003e6. Cognitive functioning (global and attention/processing speed, verbal learning and memory, and executive function domains)\u003c/p\u003e\n\u003cp\u003e7. CBSST skill learning\u003c/p\u003e\n\u003cp\u003e8. Social communication skills\u003c/p\u003e\n\u003cp\u003e9. Quality of life\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eInformation sources and search strategy\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA systematic literature search following Preferred Reporting Items for a Systematic Review and Meta-analysis of Individual Participant Data (PRISMA-IPD; 34) will be conducted. To identify relevant records, three databases will be searched. PubMed will be searched via MEDLINE using the \u0026ldquo;.mp\u0026rdquo; field extension, which includes nine search fields (Title, Abstract, Heading Word, Table of Contents, Key Concepts, Original Title, Tests \u0026amp; Measures, MeSH). PsycINFO will be searched via NCBI using the \u0026ldquo;All Fields\u0026rdquo; preset. Embase will be searched using the \u0026quot;ALL\u0026quot; field command. Additionally clinical trial registries such as clinicaltrials.gov will be searched for unpublished data. \u0026nbsp;For all databases, the search will be limited to records dating back to 2005, written in either English or German. The query will include a term referring to psychotic disorders and a term referring to CBSST to appear concurrently in the search fields. Manual reference section citation searches of included articles and previous review articles will be conducted. Google Scholar will be used for additional manual searches. A medical librarian will be consulted with the protocol at Universit\u0026auml;t Hamburg before searches will be conducted. Identified records will be handled using AI assisted tools such as Covidence or Rayan to remove duplicates and to perform the title and abstract screening.\u003c/p\u003e\n\u003cp\u003eWe will contact the authors of eligible studies and request anonymized IPD and any additional relevant studies or information. E-mails will be sent to the first and/or corresponding author of the studies. In the event of non-response, we will send reminders and attempt to contact other authors or use alternative communication methods, such as telephone. Should there be persistent uncertainty regarding the eligibility criteria and/or IPD availability due to inadequate author responses despite our efforts, the study will be excluded from the analysis.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStudy selection and data collection\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eStudy selection\u0026nbsp;\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eMP and DD will independently screen the records for inclusion and apply the eligibility criteria following a two-step screening process. First, titles and abstracts will be screened to identify potentially eligible studies. Second, full texts of potentially relevant or unclear records will be obtained and assessed against the eligibility criteria.\u0026nbsp;Disagreements between the individual judgements\u0026nbsp;will be resolved by discussion with EG and JH. When required, further information will be requested from study authors. Decisions will be recorded in a table documenting the study title, the study authors, the year of publication and the reason for exclusion. The process of study selection will be reported with a PRISMA-IPD flow diagram.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eData collection and extraction\u0026nbsp;\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eMP and EG will request IPD from all selected records. PL will merge harmonized individual participant data of all included records and add a categorical trial identifier assigning each participant to the respective trial. Data will be merged into a long format file with rows by participant and study visit/ time points. An additional categorical variable will be added identifying the number of the respective study visit. Furthermore, another continuous variable will contain information about the follow-up duration from baseline in months. The final dataset will be validated by MP and JH by examining for missing values, outliers, and duplicated values, and the adequacy of randomization (if possible with the available data), and cross-check with the summary statistics reported in the published studies. In case of any discrepancies, we will collaborate with the study authors to address and resolve the issues. When IPD are not available, two independent reviewers will extract aggregated data from the original reports. Please see preregistration record for the full list of extracted variables.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eRisk‐of‐bias assessment\u0026nbsp;\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eRisk of bias in individual studies will be assessed by MP and DD using the Version 2 of the Cochrane risk-of-bias tool for randomized trials (RoB 2; 40). Any disagreement will be resolved by discussion with JH and EG. RoB 2 uses signaling questions and an algorithm to help make judgements of \u0026lsquo;low risk\u0026rsquo;, \u0026lsquo;some concerns\u0026rsquo; or \u0026lsquo;high risk\u0026rsquo; related to five domains:\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e1. Bias arising from the randomization process\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e2. Bias due to deviations from intended interventions\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e3. Bias due to missing outcome data\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e4. Bias in measurement of the outcome\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e5. Bias in selection of the reported result\u003c/p\u003e\n\u003cp\u003eAn overall risk of bias will be determined by the tool\u0026rsquo;s algorithm. The assessment will be done for the trial\u0026rsquo;s main outcome and with respect to the assignment to the intervention (intention-to-treat effect). These judgements will be used to inform the assessment of within-study bias in the evaluation of the confidence of the evidence (see \u0026ldquo;Confidence in the evidence\u0026rdquo;) and will be included in between-study moderator analyses to test whether the effect of CBSST is dependent on a study\u0026rsquo;s risk of bias.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eAssessment of applicability\u0026nbsp;\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAccording to our eligibility criteria, the included RCTs are expected to provide evidence regarding both the efficacy in standardized research contexts and the effectiveness of interventions in real-world settings. To further evaluate potential issues related to applicability, two independent reviewers will employ the Rating of Included Trials on the Efficacy-Effectiveness Spectrum (RITES) tool (41). The RITES tool assesses domains such as participant characteristics, trial setting, intervention flexibility, and clinical relevance. Each domain is rated on a 5-point Likert scale, ranging from 1 (\u0026quot;strong emphasis on efficacy\u0026quot;) to 5 (\u0026quot;strong emphasis on effectiveness\u0026quot;) . These ratings will inform the assessment of potential indirectness in the evidence (see the \u0026ldquo;Confidence in the evidence\u0026rdquo; section).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eConfidence in the evidence\u0026nbsp;\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe will evaluate the certainty of the evidence using the GRADE (Grading of Recommendations, Assessment, Development, and Evaluations; 42) approach for our main outcome, namely levels of functioning. The GRADE framework provides a systematic method for assessing the quality of evidence and the strength of recommendations. It considers factors such as risk of bias, inconsistency of results, indirectness of evidence, imprecision, and publication bias. Evidence is rated across four levels: high, moderate, low, and very low certainty. This approach ensures a transparent and structured process for evaluating how much confidence can be placed in the findings of the included studies, ultimately guiding the formulation of reliable conclusions and recommendations.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData synthesis\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis IPD meta-analysis will include both a two- and a one staged approach. The rationale for our statistical approach follows the recommendations for practice of individual participant data meta-analyses (43) and the PRISMA-IPD criteria (34).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eEffect sizes\u0026nbsp;\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFor the two-stage approach, means and standard deviations of outcomes will be transformed into standardized mean differences (SMD) (44) and corrected for overestimation using Hedge\u0026rsquo;s g (45). Positive SMDs will indicate better outcomes in participants receiving CBSST, while negative SMDs reflect outcomes favoring control conditions. Effect sizes will be presented along with 95% confidence intervals. Number needed to treat will be estimated as a secondary measure of effect for functioning outcomes.\u003c/p\u003e\n\u003cp\u003eFor the one-stage-approach, the standardized regression-based beta-coefficient of the treatment effect with their corresponding standard error and 95% confidence intervals will be reported as measure of effect.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eSynthesis approach\u0026nbsp;\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eThe two-stage approach.\u003c/strong\u003e First, we will synthesize a summary effect size of CBSST on primary functioning outcomes at the final follow-up of each study following the two-stage approach. In the first stage IPD within a trial will be analyzed to generate study-level summary effect (i.e., Hedge\u0026rsquo;s g; see next section). In the second stage the effect sizes from each trial will be aggregated across trials using conventional two-level random-effects meta-analytical methods, which accounts for between-study heterogeneity (45). Heterogeneity of effect sizes will be evaluated using the Q-statistic and I\u0026sup2; (44, 46). All statistical analyzes within the two-stage approach will be conducted using the \u0026quot;metafor\u0026quot; package (47) implemented in RStudio.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eThe one-stage approach.\u003c/strong\u003e In a second step, we will follow the one-stage approach by combining all individual participant data in a single meta-analysis based on a mixed linear regression model stratified by trial. These models are particularly suitable for investigating how treatment effects vary between individuals or groups and have improved ability to detect differences between groups of participants over two-stage meta-analyses due to higher statistical power. Furthermore, the one-stage approach allows to separate group-level and individual-level variance. For this IPD meta-analysis, we will estimate mixed linear models to predict functioning and secondary outcomes across the follow-up visits of each study. The model will include group (treatment vs. control group), study visit and the interaction of both as fixed effects. If model convergence can be achieved, the random effect structure will include a random intercept by trial and another by participant. Time (i.e., study visit) will be included as random slope following the maximal-random approach for multilevel modelling (48). In case of case of non-convergence, the random effect structure will be gradually simplified until convergence is achieved. Marginal and conditional R\u003csup\u003e2\u003c/sup\u003e will be reported as measures of model fit. These models will be\u0026nbsp;estimated\u0026nbsp;using the \u0026lsquo;lme4\u0026rsquo; and the \u0026lsquo;lmertest\u0026rsquo; packages implemented in RStudio\u0026nbsp;(49, 50). Please see Wilkinson notation below:\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cimg 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\" style=\"width: 556px;\"\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eSubgroup and meta-regression analyses\u0026nbsp;\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe will conduct a set of study-level subgroup and meta-regression analyses within the two-stage approach. Additionally, in the one-stage approach, we will test a set of participant-level covariates using meta-regressions by pooling data from all studies and directly examining the influence of individual participant characteristics. This dual approach allows for a thorough exploration of both study- and participant-level factors. Please see below for a list of subgroup and meta-regression tests.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStudy-Level (Two-stage approach).\u003c/strong\u003e Type of comparator, study setting, type of trial (efficacy vs. effectiveness), level of therapist training, additional treatment modules (e.g., digital or cognitive remediation) will be tested by estimating separate meta-regression models in the second stage of the two-stage analysis\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eParticipant-Level (One-stage approach).\u003c/strong\u003e Diagnoses, age, gender, years of education, ethnicity/race, medication status (medicated/unmedicated), type of medication at baseline, chlorpromazine equivalent doses at baseline, depressive symptoms at baseline, positive symptoms at baseline, negative symptoms at baseline, illness status (first-episode, chronic), cognitive functioning at baseline, defeatist and asocial beliefs at baseline, psychosocial functioning at baseline, number of sessions received, therapist fidelity, and social skills at baseline will be tested as covariates and their interaction with the group by study visit effect in the one-stage models separately for each outcome and covariate. An additional exploratory model including all covariates will be estimated to determine the most relevant predictors of change.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eMotivational negative symptoms and the resulting functional impairment of people with schizophrenia represent highly important, yet unmet treatment targets. Cognitive Behavioral Social Skills Training is a promising evidence-based and targeted psychological intervention program that combines cognitive-behavioral techniques with social skills training to address the dysfunctional beliefs and social deficits common in schizophrenia. Despite many published clinical trials investigating the efficacy of CBSST on functioning and negative symptoms, the field currently lacks a meta-analytic aggregation of the overall effect sizes of CBSST on mental health outcomes as well as an empirically informed understanding of the relevant patient-level characteristics that might affect the effect of CBSST on the study outcomes. Insights into the overall efficacy of CBSST and relevant patient-level characteristics, would improve our understanding of the benefits that can be expected from CBSST, and could inform personalized treatment in clinical routine as well as the development of treatment guidelines for schizophrenia patients with negative symptoms and functional impairments.\u003c/p\u003e \u003cp\u003eTo fill this gap and to better inform treatment planning, this individual-participant-data meta-analysis aims to provide a fine-grained synthesis of the evidence on the comparative efficacy of CBSST in patients with schizophrenia. Moreover, we will investigate patient-level (e.g., age, cognitive impairment etc.) and study-level (e.g., additional digital intervention, group vs. individual format, active vs. passive comparator etc.) predictors of treatment efficacy, explore the mechanisms of change, such as skill learning and cognitive attitudes, in facilitating improvements in functioning and determine the dose of CBSST (number of sessions) needed to improve functioning.\u003c/p\u003e \u003cp\u003eOur planned IPD meta-analysis is conceptualized to mitigate the limitations of previous meta-analyses that used classical aggregation approaches at the study-level and, due to differing scopes, did not include the entire available evidence on CBSST. By leveraging the advantages of integrating more detailed information from IPD we will be able to provide estimates with increased reliability, and to explore factors that may influence these outcomes on the participant-level. Thus, our study will extend the existing literature on the treatment of functional impairment in patients with schizophrenia significantly.\u003c/p\u003e \u003cdiv id=\"Sec22\" class=\"Section2\"\u003e \u003ch2\u003eLimitations\u003c/h2\u003e \u003cp\u003eAlthough an IPD meta-analysis can offer a more elaborate analysis necessary to provide more precise answers for this topic, it is more complex and time and resource intensive. A major challenge will be acquiring IPD, harmonization, and analysis of the IPD datasets. Our main goal is to harmonize these datasets into a common format, allowing a detailed synthesis of the evidence. However, decisions regarding the exact model specification and standardization of variables will need to be made post-hoc and based on the available data. This process may require trade-offs between preserving data detail and achieving harmonization, but we will make pragmatic choices that maintain scientific rigor.\u003c/p\u003e \u003cp\u003eLastly, it is anticipated that the majority of IPDs will originate from our work group. While this offers the advantage of high data availability, it may also be prone to certain biases, such as allegiance effects when interpreting the findings. To mitigate the risk of bias in this study, we will adhere to a rigorous open science approach, wherein we publish our hypotheses and the study protocol a priori and will make any deviations from the protocol transparent. Notwithstanding our direct access to the data of most CBSST trials, it may still not be feasible to obtain IPD for some studies or outcomes, especially for those done in other work groups. We will explore potential data availability biases and consider meta-analytic models allowing the synthesis of studies providing IPD alongside those reporting only aggregate data.\u003c/p\u003e \u003c/div\u003e"},{"header":"Conclusion","content":"\u003cp\u003eIt is pivotal to identify effective interventions for the management of severe functional impairment and negative symptoms in the treatment of patients with schizophrenia. Cognitive Behavioral Social Skills Training is a targeted psychological intervention program that has been demonstrated to alleviate negative symptoms and to enhance functional outcomes in a substantial number of clinical trials. Nevertheless, a comprehensive meta-analytic synthesis of the evidence, along with explicit evidence-based recommendations, remains to be undertaken. The findings of our individual-participant-data meta-analysis will provide the insights on the efficacy and differential indications to inform treatment decision-making and guideline recommendation development. Moreover, this study will identify potential gaps in the existing literature that may warrant further investigation. The findings will be published in a peer-reviewed scientific journal and subsequently disseminated in plain language through summaries and presentations to ensure broad accessibility to facilitate implementation of evidence-based interventions in clinical practice.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cb\u003eCBSST\u003c/b\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eCognitive Behavioral Social Skills Training\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cb\u003eDSM IV, DSM 5\u003c/b\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eDiagnostic and Statistical Manual of Mental Disorders, Fourth and Fifth Editions\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cb\u003eGRADE\u003c/b\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eGrading of Recommendations, Assessment, Development, and Evaluations\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cb\u003eICD\u003c/b\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003e \u003cb\u003e9, ICD\u003c/b\u003e-\u003cb\u003e10\u003c/b\u003e-International Classification of Diseases, Ninth and Tenth Editions\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cb\u003eIPD\u003c/b\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eIndividual Participant Data\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cb\u003eIPD\u003c/b\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003e \u003cb\u003eMA\u003c/b\u003e-Individual Participant Data Meta-Analysis\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cb\u003ePRISMA\u003c/b\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003e \u003cb\u003eIPD\u003c/b\u003e-Preferred Reporting Items for a Systematic Review and Meta-analysis of Individual Participant Data\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cb\u003eRCTs\u003c/b\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eRandomized-Control Trials\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cb\u003eRITES\u003c/b\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eRating of Included Trials on the Efficacy-Effectiveness Spectrum tool\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cb\u003eSCALE\u003c/b\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eSpecify the problem, Consider all possible solutions, Assess the best solution, Lay out a plan, and Execute and evaluate the outcome\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cb\u003eSMD\u003c/b\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eStandardized Mean Differences\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cb\u003eROB 2\u003c/b\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eVersion 2 of the Cochrane risk-of-bias tool for randomized trials\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets analysed during the current study are not publicly available due to data protection and confidentality of individual participant data but are available from EG upon reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDr. Granholm has an equity interest in Granholm Consulting, Inc., a company that may potentially benefit from the research results as he receives income from the company for CBSST workshops and consulting. The terms of this arrangement have been reviewed and approved by the University of California, San Diego, in accordance with its conflict of interest policies.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eMatthias Pillny received financial support from The Federal Ministry of Education and Research Germany (BMBF) and the Free and Hanseatic City of Hamburg under the Excellence Strategy of the Federal and State Governments (UHH/VP3/4/425 IRF_2022_Pillny).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026apos; contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eConceptualization\u0026nbsp;\u0026ndash; MP, DD, EG.\u003c/p\u003e\n\u003cp\u003eFunding Acquisition\u0026nbsp;- MP.\u003c/p\u003e\n\u003cp\u003eMethodology\u0026nbsp;- MP.\u003c/p\u003e\n\u003cp\u003eWriting \u0026ndash; Original Draft\u0026nbsp;- MP.\u003c/p\u003e\n\u003cp\u003eWriting \u0026ndash; Review \u0026amp; Editing\u0026nbsp;\u0026ndash; MP, DD, JH, PL, EG.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe would like to express \u0026nbsp;our sincere gratitude to all the participants who contributed their time and effort to make these studies possible. Your commitment and willingness to share your experiences have been invaluable in advancing our understanding and improving CBSST. We deeply appreciate your trust and dedication, which have been essential in helping us pursue meaningful and impactful research. Thank you for your invaluable contribution.\u003c/p\u003e\n\u003ch3\u003eAuthor Note\u003c/h3\u003e\n\u003cp\u003eCorrespondence concerning this article should be addressed to Dr. Matthias Pillny, Clinical Psychology and Psychotherapy, Institute of Psychology, Faculty of Psychology and Human Movement Science, Universit\u0026auml;t Hamburg, Von-Melle-Park 5, 20146 Hamburg, Germany. Email: [email protected]\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eStrauss GP, Ahmed AO, Young JW, Kirkpatrick B. Reconsidering the latent structure of negative symptoms in schizophrenia: A review of evidence supporting the 5 consensus domains. Schizophr Bull. 2019;45:725\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePillny M, Lincoln TM. Predictors of improved functioning in patients with psychosis: The role of amotivation and defeatist performance beliefs. Psychiatry Res. 2016;244:117\u0026ndash;22.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSchlier B, Buck L, M\u0026uuml;ller R, Lincoln TM, Bott A, Pillny M. Time-dependent effect of antipsychotic discontinuation and dose reduction on social functioning and subjective quality of life\u0026ndash;a multilevel meta-analysis. eClinicalMedicine. 2023;65.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCella M, Roberts S, Pillny M, Riehle M, O'Donoghue B, Lyne J et al. Psychosocial and behavioural interventions for the negative symptoms of schizophrenia: a systematic review of efficacy meta-analyses. Br J Psychiatry. 2023:1\u0026ndash;11.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLincoln TM, Schlier B, M\u0026uuml;ller R, Hayward M, Fladung A-K, Bergmann N et al. Reducing Distress from Auditory Verbal Hallucinations: A Multicenter, Parallel, Single-Blind, Randomized Controlled Feasibility Trial of Relating Therapy. Psychother Psychosom. 2024:1\u0026ndash;12.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePeralta V, Garc\u0026iacute;a de Jal\u0026oacute;n E, Moreno-Izco L, Peralta D, Janda L, S\u0026aacute;nchez-Torres AM, et al. Long-Term Outcomes of First-Admission Psychosis: A Naturalistic 21-Year Follow-Up Study of Symptomatic, Functional and Personal Recovery and Their Baseline Predictors. Schizophr Bull. 2022;48(3):631\u0026ndash;42.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChang WC, Hui CLM, Tang JYM, Wong GHY, Lam MML, Chan SKW, et al. Persistent negative symptoms in first-episode schizophrenia: A prospective three-year follow-up study. Schizophr Res. 2011;133(1):22\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVentura J, Subotnik KL, Gitlin MJ, Gretchen-Doorly D, Ered A, Villa KF, et al. Negative symptoms and functioning during the first year after a recent onset of schizophrenia and 8years later. Schizophr Res. 2015;161(2):407\u0026ndash;13.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGranholm E, McQuaid J, Holden J. Cognitive-behavioral social skills training for schizophrenia: A practical treatment guide. Guilford Press; 2016.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePillny M, Krkovic K, Buck L, Lincoln TM. From memories of past experiences to present motivation? A meta-analysis on the association between episodic memory and negative symptoms in people with psychosis. 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Schizophr Res. 2011;125:152\u0026ndash;60.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePillny M, Krkovic K, Lincoln TM. Development of the Demotivating Beliefs Inventory and Test of the Cognitive Triad of Amotivation. Cogn Therapy Res. 2018;42:867\u0026ndash;77.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePillny M, Schlier B, Lincoln TM. I just don't look forward to anything. How anticipatory pleasure and negative beliefs contribute to goal-directed activity in patients with negative symptoms of psychosis. Schizophr Res. 2020;222:429\u0026ndash;36.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGranholm E, Holden J, Link PC, McQuaid JR, Jeste DV. Randomized controlled trial of cognitive behavioral social skills training for older consumers with schizophrenia: Defeatist performance attitudes and functional outcome. Am J Geriatric Psychiatry. 2013;21:251\u0026ndash;62.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGranholm E, Holden J, Link PC, McQuaidm JR. Randomized clinical trial of cognitive behavioral social skills training for schizophrenia: improvement in functioning and experiential negative symptoms. J Consult Clin Psychol. 2014;82:1173\u0026ndash;85.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGranholm E, McQuaid JR, McClure FS, Auslander LA, Perivoliotis D, Pedrelli P, et al. A randomized, controlled trial of cognitive behavioral social skills training for middle-aged and older outpatients with chronic schizophrenia. Am J Psychiatry. 2005;162(3):520\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGranholm E, Twamley EW, Mahmood Z, Keller AV, Lykins HC, Parrish EM et al. Integrated Cognitive-Behavioral Social Skills Training and Compensatory Cognitive Training for Negative Symptoms of Psychosis: Effects in a Pilot Randomized Controlled Trial. Schizophr Bull. 2021:1\u0026ndash;12.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGranholm E, McQuaid JR, McClure FS, Link PC, Perivoliotis D, Gottlieb JD, et al. Randomized controlled trial of cognitive behavioral social skills training for older people with schizophrenia: 12-month follow-up. J Clin Psychiatry. 2007;68:730\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGranholm E, Holden J, Worley M. Improvement in negative symptoms and functioning in Cognitive-Behavioral Social Skills Training for Schizophrenia: mediation by defeatist performance attitudes and asocial beliefs. Schizophr Bull. 2018;44:653\u0026ndash;61.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBighelli I, Wallis S, Reitmeir C, Schwermann F, Salahuddin NH, Leucht S. Effects of psychological treatments on functioning in people with Schizophrenia: a systematic review and meta-analysis of randomized controlled trials. Eur Arch Psychiatry Clin NeuroSci. 2023;273(4):779\u0026ndash;810.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRajji TK, Mamo DC, Holden J, Granholm E, Mulsant BH. Cognitive-Behavioral Social Skills Training for patients with late-life schizophrenia and the moderating effect of executive dysfunction. Schizophr Res. 2022;239:160\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMahmood Z, Van Patten R, Keller AV, Lykins HC, Perivoliotis D, Granholm E, et al. Reducing negative symptoms in schizophrenia: Feasibility and acceptability of a combined cognitive-behavioral social skills training and compensatory cognitive training intervention. Psychiatry Res. 2021;295:113620.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eUsall J, Haro J, Ochoa S, Marquez M, Araya S. group N. 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BMJ. 2010;340:c221.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDebray TPA, Moons KGM, van Valkenhoef G, Efthimiou O, Hummel N, Groenwold RHH, et al. Get real in individual participant data (IPD) meta-analysis: a review of the methodology. Res Synthesis Methods. 2015;6(4):293\u0026ndash;309.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eStewart LA, Clarke M, Rovers M, Riley RD, Simmonds M, Stewart G, et al. Preferred Reporting Items for a Systematic Review and Meta-analysis of Individual Participant Data: The PRISMA-IPD Statement. JAMA. 2015;313(16):1657\u0026ndash;65.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGranholm E, Holden JL, Sommerfeld D, Rufener C, Perivoliotis D, Mueser K, et al. Enhancing assertive community treatment with Cognitive Behavioral Social Skills Training for schizophrenia: Study protocol for a randomized controlled trial. Trials. 2015;16:438.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBrowne J, Harvey PD, Buchanan RW, Kelly DL, Strauss GP, Gold JM et al. A Longitudinal Examination of Real-World Sedentary Behavior in Adults with Schizophrenia-Spectrum Disorders in a Clinical Trial of Combined Oxytocin and Cognitive Behavioral Social Skills Training. Behav Sci (Basel). 2022;12(3).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGranholm E, Holden J, Dwyer K, Mikhael T, Link P, Depp C. Mobile-Assisted Cognitive Behavioral Therapy for Negative Symptoms: Open Single-Arm Trial With Schizophrenia Patients. JMIR Mental Health. 2020;7:e24406.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGranholm E, Holden JL, Dwyer K, Link P. Mobile-assisted cognitive-behavioral social skills training in older adults with schizophrenia. 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Br J Anaesth. 2019;123(5):554\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eStewart GB, Altman DG, Askie LM, Duley L, Simmonds MC, Stewart LA. Statistical Analysis of Individual Participant Data Meta-Analyses: A Comparison of Methods and Recommendations for Practice. PLoS ONE. 2012;7(10):e46042.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHedges LV, Olkin I. Statistical methods for meta-analysis. New York: Academic; 1985. p. 369.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBorenstein M, Hedges LV, Higgins JPT, Rothstein HR. Introduction to meta-analysis. West Sussex: Wiley; 2009.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHiggins JPT, Thompson SG, Deeks JJ, Altman DG. Measuring inconsistency in meta-analyses. BMJ. 2003;327:557\u0026ndash;60.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eViechtbauer W. Conducting meta-analyses in R with the metafor. J Stat Softw. 2010;36:1\u0026ndash;48.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBarr DJ, Levy R, Scheepers C, Tily HJ. Random effects structure for confirmatory hypothesis testing: Keep it maximal. J Mem Lang. 2013;68:255\u0026ndash;78.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBates M\u0026auml;chler. Bolker, Walker. Fitting Linear Mixed-Effects Models Using lme4. J Stat Softw. 2015;67:1\u0026ndash;48.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKuznetsova, Brockhoff C. lmerTest Package: Tests in Linear Mixed Effects Models. J Stat Softw. 2017;82:1\u0026ndash;26.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":true,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"systematic-reviews","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"sysr","sideBox":"Learn more about [Systematic Reviews](http://systematicreviewsjournal.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/sysr/default.aspx","title":"Systematic Reviews","twitterHandle":"@MedicalEvidence","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Schizophrenia, CBSST, functioning, social recovery, negative symptoms, evidence-based, psychotherapy, psychosis, amotivation, defeatist beliefs, social skills","lastPublishedDoi":"10.21203/rs.3.rs-5377914/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5377914/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eCognitive Behavioral Social Skills Training (CBSST) is a targeted psychological intervention designed to improve daily functioning and to address negative symptoms in individuals diagnosed with schizophrenia. Despite evidence from clinical trials suggesting beneficial effects of CBSST on functioning and negative symptoms, the overall efficacy of CBSST remains to be quantified. Furthermore, potential moderators and mediators of treatment outcomes remain elusive. This protocol outlines an Individual Participant Data Meta-Analysis (IPD-MA) with the objective to examine the efficacy of CBSST on psychosocial functioning in schizophrenia.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eIn accordance with the Preferred Reporting Items for a Systematic Review and Meta-analysis of Individual Participant Data (PRISMA-IPD) guidelines, we will conduct a systematic literature search and employ two-stage and one-stage meta-analytical approaches to ensure robust data synthesis. The meta-analytical models will evaluate the overall effect of CBSST relative to control treatments in randomized controlled trials, identify participant-level (e.g., age, cognitive impairment) and study-level (e.g., individual vs. group settings) predictors of change, and explore the mechanisms that mediate improvement in functioning, such as skills acquisition and cognitive restructuring of defeatist attitudes. Furthermore, the analysis will attempt to determine the optimal amount of CBSST sessions required to enhance functioning and evaluate the impact of patient-level factors driving delivered dosage.\u003c/p\u003e\u003ch2\u003eDiscussion\u003c/h2\u003e \u003cp\u003eThe objective of this study is to contribute to the existing literature by addressing the current gaps in understanding the efficacy of CBSST and identifying critical factors for treatment success. Our findings will have the potential to inform personalized treatment planning and the development of clinical guideline recommendations focusing on functional outcomes and negative symptoms in people with schizophrenia.\u003c/p\u003e\u003ch2\u003eRegistration:\u003c/h2\u003e \u003cp\u003esubmitted October 23rd, 2024 (605353)\u003c/p\u003e","manuscriptTitle":"Effect of Cognitive Behavioral Social Skills Training on Functioning in Schizophrenia: Protocol for an Individual Participant Data Meta-Analysis of Randomized Controlled Trials","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-04-02 10:56:40","doi":"10.21203/rs.3.rs-5377914/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Major revision","date":"2025-10-05T23:04:51+00:00","index":"","fulltext":""},{"type":"reviewerAgreed","content":"","date":"2025-04-19T17:20:47+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-02-07T17:39:32+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-11-15T04:20:18+00:00","index":"","fulltext":""},{"type":"submitted","content":"Systematic Reviews","date":"2024-11-02T07:12:14+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"systematic-reviews","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"sysr","sideBox":"Learn more about [Systematic Reviews](http://systematicreviewsjournal.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/sysr/default.aspx","title":"Systematic Reviews","twitterHandle":"@MedicalEvidence","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"2ea8fb66-da16-4315-8375-866962baf9a4","owner":[],"postedDate":"April 2nd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2026-03-09T16:02:26+00:00","versionOfRecord":{"articleIdentity":"rs-5377914","link":"https://doi.org/10.1186/s13643-026-03124-x","journal":{"identity":"systematic-reviews","isVorOnly":false,"title":"Systematic Reviews"},"publishedOn":"2026-03-05 15:57:25","publishedOnDateReadable":"March 5th, 2026"},"versionCreatedAt":"2025-04-02 10:56:40","video":"","vorDoi":"10.1186/s13643-026-03124-x","vorDoiUrl":"https://doi.org/10.1186/s13643-026-03124-x","workflowStages":[]},"version":"v1","identity":"rs-5377914","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5377914","identity":"rs-5377914","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}