Synchronous online group MBCT vs guided asynchronous iMBCT in depressed sample: randomized clinical trial with a 3-month follow-up

Synchronous online group MBCT vs guided asynchronous iMBCT in depressed sample: randomized clinical trial with a 3-month follow-up | 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 Synchronous online group MBCT vs guided asynchronous iMBCT in depressed sample: randomized clinical trial with a 3-month follow-up Jan Wardęszkiewicz, Paweł Holas, Gerhard Andersson This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7166236/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background Online Mindfulness-Based Cognitive Therapy (iMBCT) is a promising intervention for mental health, but its effectiveness in reducing depressive symptoms remains underexplored. While key mechanisms of change have been identified in traditional MBCT, their role in online delivery formats needs further investigation. Methods In this randomized clinical trial, 170 individuals with mild to moderate depression were assigned to a 6-week synchronous iMBCT group (n = 58), asynchronous iMBCT group (n = 59), or waitlist control (n = 53). Depression, anxiety, mindfulness, cognitive fusion, rumination, self-compassion, resilience, and experiential avoidance were assessed at baseline, post-treatment, and 3-month follow-up. Results Posttest assessments were completed by 42 participants (72%) in the synchronous group, 32 (54%) in the asynchronous group, and 51 (96%) in the waitlist control condition. Both iMBCT formats significantly reduced depressive symptoms compared to the control group, with sustained effects at follow-up. Mindfulness and cognitive defusion emerged as significant mediators, explaining 52% of the variance in the post-treatment depression severity. Additionally, participants in both interventions showed decreased rumination and anxiety, and increased self-compassion and resilience - effects maintained at follow-up. Conclusions Synchronous and asynchronous iMBCT formats are effective in reducing depressive symptoms and enhancing psychological well-being. These findings support the use of online mindfulness-based interventions as scalable, accessible alternatives to traditional therapy. Psychology Psychiatry Online Mindfulness-Based Cognitive Therapy Depression Internet intervention Mechanisms of change iMBCT Figures Figure 1 1. Introduction Depression is a prevalent mental health disorder, affecting approximately 5% of adults worldwide (World Health Organization, 2023 ). Individuals experiencing depression commonly report a range of emotional distress, including feelings of guilt, worthlessness, and hopelessness, as well as sleep disturbances, changes in appetite, and persistent low mood (Radloff, 1977 ). Beyond these symptoms, depression disrupts multiple aspects of functioning, including cognitive (Baune & Air, 2016 ), social (Steger & Kashdan, 2009 ), biological (Cui et al., 2024 ; Nestler et al., 2002 ), psychological (Beck et al., 1993 ; Maier & Seligman, 1976 ), and occupational domains (Wang et al., 2004 ). Despite the documented efficacy of evidence-based psychotherapies and pharmacological treatments, access to mental health care remains critically limited worldwide (Wainberg et al., 2017 ). A global analysis of the treatment gap between 2000 and 2019 revealed that the proportion of individuals receiving minimally adequate treatment for depression ranged from just 3% in low-income countries to 23% in high-income countries (Moitra et al., 2022 ). This persistent disparity is multifaceted and can be attributed to several factors, including the limited availability of trained specialists, the high cost of treatment, geographical barriers to accessing services, and the persistent stigma surrounding mental disorders (World Health Organization, 2022 ). Given these challenges, there is an urgent need to explore scalable alternatives that can bridge this gap and expand access to mental health care. 1.1 Internet-based psychological interventions One promising approach is internet-based psychological interventions, which offer a cost-effective and scalable solution to mental health service delivery (Schueller & Torous, 2020 ). These interventions have demonstrated satisfactory effectiveness in treating mental health disorders, as evidenced by numerous meta-analyses (Guo et al., 2021 ; Fischer-Grote et al., 2024 ; Wang et al., 2023 ; Pauley et al., 2023 ), including depression (Moshe et al., 2021 ; Karyotaki et al., 2021 ). However, despite their growing empirical support, more research is still needed to ensure their safe and effective integration into routine primary care (Smith et al., 2023 ). 1.2 Online mindfulness-based interventions Among the various internet-based psychological interventions, online mindfulness-based interventions (MBIs) have been increasingly studied as a promising approach for reducing depressive symptoms (meta-analyses: Sommers-Spijkerman et al., 2021 ; Spijkerman et al., 2016 ). Research indicates that in-person mindfulness interventions target key cognitive and emotional mechanisms that contribute to the persistence of depression, including rumination (Li et al., 2022 ), worry (van der Velden et al., 2015 ), and repetitive negative thinking (MacKenzie et al., 2018 ). Additionally, MBIs have been associated with improvements in self-regulation (Wang et al., 2024 ), self-compassion (Ha & Kim, 2023), and resilience (Pérez-Aranda et al., 2021 ), all of which contribute to the reduction of depressive symptoms. While a significant body of research has examined these mechanisms within in-person programs, further studies are needed to determine whether online adaptations effectively engage the same processes. As research on online MBIs has expanded exponentially (Ferreira & Demarzo, 2024 ), challenges related to standardized reporting have become increasingly evident (Wolever et al., 2022 ). The term 'online intervention' encompasses a wide range of delivery methods, including guided and unguided formats, synchronous and asynchronous sessions, as well as mobile- and web-based platforms (Smoktunowicz et al., 2020 ), making consistent classification and comparison difficult. These distinctions are crucial, as delivery format appears to influence intervention outcomes. For example, one study found that an online (synchronous) MBIs had a greater impact on stress reduction compared to an unguided, asynchronous program (Wolever et al., 2022 ). A meta-analysis by Taylor et al. ( 2021 ) suggested that unguided MBIs had a smaller effect on depression, mindfulness, and quality of life compared to non-digital unguided interventions (e.g., textbook and CD-based programs). Furthermore, these variations refer only to the technical aspects of intervention delivery, without accounting for substantial differences in content, duration, therapeutic approach, or symptom measurement/diagnosis methods, all of which may further influence intervention efficacy. To address these issues there is an agreement that more good quality randomized controlled trials (RCTs) are needed, comparing different online MBIs formats (Taylor et al., 2021 ), such as synchronous and asynchronous (Toivonen et al., 2017 ; Schwarze & Gerler, 2015 ) or reaching specific clinical populations (Sevilla-Llewellyn-Jones et al., 2018 ). 1.3 Online Mindfulness-Based Cognitive Therapy Mindfulness-Based Cognitive Therapy (MBCT) is one of the most extensively studied MBIs (Zhang et al., 2021 ). This is an 8-week program consisting of weekly group sessions lasting 2 to 2.5 hours. The course integrates formal mindfulness practices, including the body scan, sitting meditation, and mindful movement, with cognitive-behavioral therapy components such as psychoeducation on depression or behavioral activation (Sipe & Eisendrath, 2012 ). Originally developed to prevent relapse in recurrent depression (Teasdale et al. 2000 ), MBCT has demonstrated effectiveness in this area, as supported by meta-analyses (Piet & Hougaard, 2011 ; Kuyken, et al., 2016 ; McCartney et al., 2021 ). However, research also indicates its efficacy in treating current depressive episodes (meta-analyses: Goldberg et al., 2019 ; Tseng et al., 2023 ). While MBCT is well established in face-to-face settings, its online adaptation (iMBCT) has thus far demonstrated only preliminary evidence of effectiveness in reducing stress (Dowd et al., 2015 ), emotional distress (Cillessen et al., 2018 ; Holas & Wardęszkiewicz, under review), and symptoms of anxiety and depression (Nissen et al., 2020 ; Segal et al., 2020 ; Seritan et al., 2022 ). However, no study to date has directly compared the effectiveness of different iMBCT delivery formats in treating depression. Prior research suggests that guided psychological interventions are associated with higher adherence and greater symptom reduction than unguided approaches (Berger et al., 2011 ), including within online mindfulness interventions (Wolever et al., 2022 ). While both synchronous and asynchronous iMBCT formats can include guidance, they differ substantially in the mode and immediacy of therapist interaction - potentially affecting engagement and outcomes. Notably, asynchronous iMBCT has been associated with higher attrition rates (Holas & Wardęszkiewicz, under review), suggesting the delivery format itself may play a critical role. Despite these concerns, no study has directly compared synchronous and asynchronous iMBCT in individuals with major depressive disorder, leaving an important gap in understanding the impact of delivery method on treatment effectiveness and adherence. 1.3 Present study The present study aims to evaluate the effectiveness of an online adaptation of MBCT in both synchronous and asynchronous formats in a sample of individuals with depression. Given the high heterogeneity of online MBI formats, which poses a persistent challenge for meta-analytic synthesis (Gong et al., 2023 ), it is crucial to also investigate existing, structured and standardized interventions in parallel with the development and evaluation of new approaches. Additionally, as the depressed population is particularly vulnerable, selecting a well-established, evidence-based intervention is essential. Among MBIs, MBCT stands out as one of the most rigorously studied and empirically supported programs, particularly for clinical populations (Zhang et al., 2021 ). Unlike other online MBIs, which vary in structure and theoretical underpinnings, MBCT is a manualized program with well-defined protocols, making it a logical candidate for digital adaptation and larger-scale implementation. Despite this, research on iMBCT remains limited, particularly in individuals with clinical depression. As the debate regarding the most optimal delivery format remains unresolved, further high-quality RCTs are needed to clarify their comparative effectiveness. To address this gap, participants in the present study were planned to be randomly assigned to either online synchronous group MBCT or asynchronous iMBCT, with a waiting-list control group serving as a comparator. 2. Methods 2.1 Design In the present study, our objective was to assess the efficacy and mechanisms of change associated with the online, six-week Mindfulness-Based Cognitive Therapy (MBCT) intervention for individuals with mild-to-moderate depression. The study employed a three-arm design, comprising an asynchronous guided group iMBCT, an online synchronous group iMBCT, and a control group assigned to a waiting list. Despite the completion of pre-test and post-test questionnaires, participants were asked to complete a follow-up assessment after a three-month interval. The study was approved by the Ethics Committee of the Psychology Faculty of the University of Warsaw (NR:11/04/2023) and registered in the Clinical Trial Register (NCT05919875). 2.2 Participants Participants were recruited through the Internet. The advertisements were primarily posted on social media platforms and were widely shared due to the voluntary participation of individuals who expressed appreciation for the project. Additionally, information about the study was published on university websites or included in newsletters. The advertisements specified that the project was intended for adults experiencing significant deterioration in psychological functioning who wished to develop or improve self-regulation skills. The landing page explicitly stated that individuals experiencing severe depressive episodes, in crisis, diagnosed with psychotic or bipolar disorders, or currently undergoing psychotherapy were ineligible to participate. A total of 502 individuals registered on the platform, of whom 444 completed all required questionnaires. Of these, 117 were excluded due to ongoing psychotherapy, 33 did not exhibit depressive symptoms, and 12 reported severe depression and were referred to psychological support centers. Among the 282 structured interviews conducted, 198 participants met the inclusion criteria; however, 28 did not complete all required questionnaires. Ultimately, 170 participants were randomized into one of three conditions: the synchronous iMBCT group (n = 58), the asynchronous iMBCT group (n = 59), or the waitlist control group (WLC; n = 53). Characteristics of the sample are shown in Table 1 and Flow chart 1. Table 1. Sociodemographic characteristic of the sample iMBCT synchronous (n = 58) iMBCT asynchronous (n = 59) WLC (n = 53) Man 13 9 7 Woman 45 50 46 Mean age 3 9 ,5 (SD = 10) 36 (SD = 10.5) 37(SD = 10) Higher education 48 47 46 Secondary education 6 5 3 Elementary education 0 2 0 Studying 4 5 3 Metropolitan city 26 28 24 Large city 13 9 13 Medium city 5 7 5 Small city 3 6 5 Village 11 9 6 Financial situation (1–6) 4.17 (SD = 1.24) 4.20 (SD = 1.20) 4.32(SD = 1.0) 2.3 Inclusion and exclusion criteria The inclusion criteria were: (1) being over 18 years old, (2) fluency in the Polish language, (3) meeting the initial screening cut-off for mild depression on the CESD-20 (≥ 16 points), (4) having a diagnosed mild or moderate depressive episode as assessed by the M.I.N.I. structured online interview (Sheehan et al., 1998 ), and (5) agreeing to the study protocol and randomization, including the possibility of being assigned to the waiting-list group. At screening both depression assessment tools were used to increase the validity of measure. In cases where only one cutoff score was exceeded, the final decision regarding inclusion was moved to the clinical interview. The exclusion criteria were: (1) severe depression or suicidality, (2) current participation in psychotherapy, (3) a diagnosis of substance use disorder, psychotic disorder, or bipolar disorder, as assessed in the M.I.N.I. structured online interview, and (4) recent modifications to or instability in psychiatric medication. 2.4 Interventions 2.4.1 6-week synchronous iMBCT In the iMBCTs format, participants were assigned to 4 groups of up to 15 individuals based on their indicated date preferences. Their profiles on the study platform were moved to the appropriate group, ensuring that each participant could access only the materials, announcements, and chat box specific to their group. Participants received email reminders about upcoming meetings and encouragement to engage in practice. If a participant remained inactive for five consecutive days, they received a gentle reminder containing psychoeducational content on topics such as perfectionism, the importance of habit formation, negative thought patterns, or difficult emotions. The meetings were conducted online via Google Meet or Zoom. Each session was led by an experienced mindfulness teacher with an MBCT certification, accompanied by an assistant responsible for technical support. In this study, the training was conducted by two male and two female teachers, each of whom was assigned to a single group for the entire six-week duration. The program was a shortened to 6-week adaptation (Holas et al., under review) of the standard MBCT protocol. The session titles were as follows: Table 2 6-week iMBCT program Week Topic of the meeting Content Exercises/ Homework 1. Awareness and automatic pilot Acting with(out) full awareness, raisin exercise, habitual patterns of distraction Mindful eating, Body scan 2. Living in our heads Tendency to be caught up in thoughts about the past and future; relationship between thoughts and feelings, body sensations Sitting meditation, body scan. calendar of pleasant experiences 3. Being present in the body Recognizing distracted mind; body as a gate to the mind and a breath as a stabilizer of attention Three-minute breathing space, Hatha yoga, sitting meditation, calendar of unpleasant experiences 4. Recognizing aversion identifying automatic reactions to discomfort, particularly the tendency to avoid or suppress difficult emotions. Three-minute breathing space, Hatha yoga, sitting meditation, 5. Allowing and Letting be practice of acceptance; turning toward difficulty meditation Meditation of difficulties, three-minute breathing space 6. How can I best take care of myself? self-care and self-regulation strategies Behavioral activation, three-minute breathing space, sitting meditation After each meeting, participants received a summary of the session, a workbook, and guided meditation recordings for the upcoming week via the study platform. They could use the chat box to communicate with each other or seek guidance from the researcher or a psychologist with expertise in mindfulness, who responded to content-related inquiries. 2.4.2 6-week asynchronous iMBCT In the iMBCTa format, participants formed a single group of 58 individuals. On the dedicated study platform, all participants had access to a shared panel that included a chat box and study materials—audio recordings and a workbook—which were unlocked weekly in accordance with the session themes. The program was a pre-recorded equivalent of the synchronous version. Each week, participants received audio recordings introducing a new topic, guided meditation exercises (e.g., body scan, sitting meditation), reflective questions, psychoeducational content with emotional support, and instructions for the upcoming week. Similar to the synchronous condition, participants were reminded about the upcoming new sessions and encouraged to engage in daily practice. In cases of inactivity, automated reminder emails were sent, following the same procedure as in the synchronous format. To sustain the activity on the platform and provide support in situations of self-doubt, participants could use the chat box for communication with themselves and with a psychologist, who was answering few times a day. 2.4.3 Control group After randomization, 53 participants were redirected to the "waiting-list" webpage on the platform, where they had access to a dedicated chat box exclusively for their group. Throughout the six-week waiting period, the group did not receive any form of intervention. During this time, three reminder emails were sent to inform participants about the study procedure and the mandatory second assessment required to gain access to the intervention. Upon completing all obligatory questionnaires, participants were granted access to the asynchronous iMBCT intervention. 2.5 Symptom Measures 2.5.1 Primary outcomes 2.5.1.1 Depression To enhance the validity of depression assessment prior to the interview, a second measure was utilized. The Center for Epidemiologic Studies Depression Scale (CES-D) is a widely used self-report tool designed to assess depressive symptoms in the general population (Radloff, 1977 ). Participants respond to 20 items on a 4-point scale, with total scores ranging from 0 to 60, where higher scores indicate greater depressive symptomatology. The tool demonstrated strong psychometric properties, with Cronbach’s alpha coefficients of .89 at baseline, .92 post-intervention, and .90 at follow-up, indicating high internal consistency. 2.5.1.2 Anxiety The GAD-7 (Spitzer et al., 2006) is a 7-item questionnaire assessing the severity of Generalized Anxiety Disorder (GAD) symptoms, including nervousness, excessive worry, restlessness, and difficulty relaxing. Participants rate how often they experienced symptoms over the past 2 weeks on a 4-point scale (0 = not at all, 3 = nearly every day), with total scores ranging from 0 to 21. The GAD-7 demonstrates strong reliability and validity across various populations (Spitzer et al., 2006; Murray et al., 2010; Kroenke et al., 2007). Cronbach’s alpha for this scale was .87 in the pre-test, .88 in post-test and .87 in follow-up. 2.5.2. Process measures 2.5.2.1 Mindfulness Levels of mindfulness were measured with the Five Facet Mindfulness Questionnaire (FFMQ) shortened from original 39 items (Baer et al., 2008 ) to 24 items by Bohlmeijer and collaborators (2011). It is a self-report tool, designed to measure different aspects of mindfulness. It assesses five key components: observing, describing, acting with awareness, nonjudging of inner experience, and nonreactivity to inner experience. The FFMQ-24 has been used to assess mindfulness skills in relation to mental health, showing moderate – strong associations with experiential avoidance, depression and anxiety (Ådnøy et al., 2023 ). Cronbach’s alpha for this scale was .87 in the pretest, .92 in posttest and .94 in follow-up. 2.5.2.2 Resilience Resilience was measured with the SPP-25 (Skala Pomiaru Prężności – Resilience Measurement Scale). It is a Polish, 25-item self-report questionnaire designed to assess psychological resilience, understood as an individual’s ability to adapt effectively to stress, adversity, and life challenges (Ogińska-Bulik & Juczyński, 2008). The scale conceptualizes resilience as a relatively stable personality trait that facilitates coping with both traumatic experiences and everyday stressors. Participants respond to each item using a 5-point Likert scale (0 = strongly disagree to 4 = strongly agree), with total scores ranging from 0 to 100, where higher scores indicate greater resilience. In our study the scale has demonstrated good internal consistency (Cronbach’s α = .92 in pretest, .93 in posttest and .91 in follow-up). 2.5.2.3 Self- Compassion Scale Short-Form The Self-Compassion Scale – Short Form (SCS-SF) (Raes et al., 2011; Polish validation: Holas et al., 2023) was used to measure self-compassion. The SCS-SF consists of 12 items, rated on a five-point scale. The SCS-SF is strongly correlated with the long form of the scale (r ≥ .97) and demonstrated consistently high internal reliability across populations (Neff & Pommier, 2013; Werner et al., 2012), with a reliability of Cronbach's α = .80 in the pretest, .87 in posttest and .75 in a follow-up measure in our study. 2.5.2.4 Cognitive-fusion scale Cognitive fusion was assessed using the Cognitive Fusion Questionnaire-7 (CFQ-7), a 7-item self-report measure designed to evaluate the extent to which individuals become entangled with their thoughts and experience difficulty distancing themselves from them (Gillanders et al., 2014). Participants rate items on a 7-point Likert scale (1 = never true to 7 = always true), with higher scores indicating greater cognitive fusion. The Polish validation confirmed its unidimensional structure and demonstrated strong psychometric properties (Baran et al., 2019 ). In the present study, Cronbach’s α ranged from .91 to .94. 2.5.2.5 Rumination In the present study The Ruminative Responses Scale (RRS), a 22-item self-report questionnaire was used to assess rumination, a cognitive style characterized by a repetitive and passive focus on one's distress and its causes (Nolen-Hoeksema & Morrow, 1991). Participants respond to statements on a 4-point Likert scale (1 = almost never to 4 = almost always), with higher scores indicating greater rumination. The scale evaluates how individuals repetitively dwell on negative emotions and thoughts rather than engaging in active problem-solving. The RRS has demonstrated strong internal consistency, with Cronbach’s α- .90 in the pretest, .92 in posttest, .90 in a follow-up assessment. 2.5.2.6 Experiential Avoidance Experiential avoidance was assessed using the Brief Experiential Avoidance Questionnaire (BEAQ), a 15-item self-report measure designed to evaluate the tendency to evade or suppress unpleasant internal experiences, such as distressing emotions, thoughts, or bodily sensations (Gámez et al., 2014). The Polish validation study confirmed its bifactorial structure, identifying two dimensions: cognitive-emotional avoidance (CEA) and behavioral avoidance (BA) (Wardęszkiewicz & Holas, 2024). BEAQ items are rated on a 6-point Likert scale (1 = strongly disagree to 6 = strongly agree), with higher scores reflecting greater experiential avoidance. In the present study, Cronbach’s α ranged from .81 to .85, indicating good internal consistency. 2.5.7 Negative effects Negative effects were assessed using the Negative Effects Questionnaire (NEQ; Rozental et al., 2014). Following the intervention, participants responded to 20 items (e.g., 'Difficult memories came back' or 'I felt anxious'), rating the intensity of specific symptoms on a scale from 0 ('not at all') to 4 ('extremely') and linking them to either intervention or external factors. The Cronbach’s α was .95 in the validation study (Rozental et al., 2019 ). 2.6 Data analysis In order to assess the effectiveness of the intervention, an analysis using linear mixed models (LMM) was conducted. The analyses were based on a 3x3 design, including three groups (control, synchronous, and asynchronous) and three measurement points (although data for the control group were only available for two time points). The interaction between these two factors was included as fixed effects. Additionally, participant ID was included as a random effect to account for inter-individual variance. This model can be expressed using the following equation: $$\:{Y}_{ij}={\beta\:}_{0}+{\beta\:}_{1}\cdot\:{Group}_{i}+{\beta\:}_{2}\cdot\:{Measurement}_{j}+\left({\beta\:}_{3}\cdot\:{Group}_{i}\cdot\:{Measurement}_{j}\right)+{u}_{i}+{\epsilon\:}_{ij}$$ ; \(\:{Y}_{ij}\) – outcome for participant i at measurement j \(\:{\beta\:}_{0}\) – intercept (constant) \(\:{\beta\:}_{1},\:{\beta\:}_{2},{\beta\:}_{3}\) – regression coefficients for fixed effects \(\:{u}_{i}\) – random effect for participant i \(\:{\epsilon\:}_{ij}\) – random error In the present study the proportion of individuals who completed the third measurement accounted for less than half of the original sample. Based on the analyses by Chakraborty and Gu (2009), it was decided to use mixed models without imputation. Their research suggests that this approach is more efficient and leads to more reliable results, especially when dealing with a high percentage of missing data. To determine the mechanisms underlying the relationship between group membership and depression severity, a series of mediation analyses with parallel mediators was conducted using PROCESS macro by A. Hayes (Model 4). In each model, group membership served as the independent variable while depression severity at posttest as the dependent variable. Baseline scores of given variables were included as covariates to control for pre-existing differences. The significance of indirect effects was assessed using a bias-corrected bootstrapping procedure with 5000 resamples. Indirect effects were considered statistically significant if the 95% confidence interval did not include zero. Both the total indirect effect and the specific indirect effects of each mediator were analyzed. Partial mediation was inferred when the direct effect of group membership on depression severity remained significant after including the mediators in the model. To explore whether participants who dropped out of the study differed from those who completed it, a series of independent-samples t-tests were conducted on baseline demographic and psychological variables. These analyses aimed to identify potential predictors of attrition by comparing completers and non-completers across key characteristics measured prior to the intervention. In addition to the full-sample comparison, analyses were also conducted separately within the synchronous and asynchronous conditions to examine whether dropout patterns varied by intervention format. 3. Results 2.1 Effects 2.1.1 Depression (CES-D) The model was evaluated using BIC = 2432.98. Fixed effects explained 31.4% of CESD variance (marginal R² = .314), while both fixed and random effects accounted for 53.7% (conditional R² = .537). ICC = .223 indicated that 22.3% of variance was due to random effects. A significant group effect was found ( F (2, 175.31) = 7.53, p < .001), with higher depression levels in the control group than in the asynchronous ( p < 0.001) and synchronous ( p = .008) groups. No significant difference was observed between the intervention groups ( p = .068). A significant time effect ( F (2, 205.10) = 76.97, p < .001) showed a decline in CESD scores from the first to later measurements (both p < .001), with no significant difference between the posttest and follow-up assessments ( p = .129). A significant interaction ( F (3, 202.43) = 13.50, p < .001) indicated that depression severity remained stable in the control group ( F (1, 176.47) = 2.98, p = .086), whereas both intervention groups showed significant reductions in the posttest and follow-up (asynchronous: F (2, 210.64) = 57.44, p < .001; synchronous: F (2, 206.81) = 33.70, p < .001). No significant group differences were found at baseline ( F (2, 297.49) = 0.61, p = .546), confirming similar initial depression levels. However, differences emerged in posttest ( F (2, 320.73) = 19.14, p < .001) and follow-up ( F (1, 331.53) = 4.31, p = .039). Post hoc analyses showed that at posttest, the control group had significantly higher depression scores than both the asynchronous ( p < .001) and synchronous ( p < 0.001) groups, with no difference between the intervention groups ( p = .096). At follow-up, depression was higher in the synchronous than in the asynchronous group ( p = .039). Estimated marginal means are provided in Table 5 . Table 5 Estimated marginal means for CESD by measurement time and group membership Measurement Group M SE 95% CI LL UL 1 WLC 26.55 1.21 24.17 28.92 asynchronous 27.86 1.14 25.62 30.11 synchronous 28.33 1.15 26.06 30.60 2 WLC 24.12 1.22 21.72 26.51 asynchronous 12.69 1.47 9.80 15.58 synchronous 16.94 1.32 14.35 19.54 3 WLC - - - - asynchronous 12.60 1.72 9.22 15.99 synchronous 17.80 1.82 14.22 21.39 The parameters for fixed effects are presented in Table 6 . The analysis showed that depression severity was significantly higher in the control group and significantly lower in the asynchronous group compared to the reference group (synchronous). CESD scores were higher at the first measurement compared to the reference measurement (third measurement)—these parameters confirm the post hoc pairwise comparisons. Table 6 Regression parameters for fixed effects in the model explaining CESD. Parameters b SE t p 95% CI LL UL Intercept 17.80 1.82 328.16 < 0.001 14.22 21.39 Pretest 10.52 1.95 222.05 < 0.001 6.69 14.36 Posttest -0.86 2.00 205.12 0.667 -4.80 3.08 WLC 7.17 1.80 312.94 < 0.001 3.64 10.70 Asynchronous -5.20 2.51 331.53 0.039 -10.13 -0.27 Pretest * WLC -8.95 2.05 187.69 < 0.001 -12.99 -4.91 Pretest * asynchronous 4.74 2.68 224.09 0.079 -0.55 10.03 Posttest * asynchronous 0.95 2.80 197.69 0.736 -4.58 6.47 2.1.3 Anxiety The model was evaluated using BIC = 1947.73. Fixed effects explained 30.5% of variance (R² = .305), while total variance explained was 56.1% (R² = .561). ICC = 0.256 indicated that 25.6% of variance was due to random effects. A significant group effect ( F (2, 167.25) = 76.39, p = .002) showed that anxiety was higher in the control group than in asynchronous ( p < .001) and synchronous ( p = 0.001) groups, with no difference between intervention groups ( p = .528). A significant time effect ( F (2, 192.82) = 80.16, p < .001) revealed a decline in anxiety from the first to later measurements (both p < .001), with no significant difference between the second and third time points ( p = .093). A significant interaction ( F (3, 190.69) = 11.47, p < .001) indicated that anxiety remained stable in the control group, while both intervention groups showed significant reductions in later assessments ( p < .001). No significant group differences were found at baseline ( p = 0.346) or at the final assessment ( p = .372), but the control group had higher anxiety than both intervention groups at the second time point ( p < .001). No difference was observed between the synchronous and asynchronous groups ( p = 1.000). 2.1.4 Cognitive Fusion The model was assessed using BIC = 2237.79. Fixed effects accounted for 24.0% of variance (R² = .240), while the total explained variance reached 62.8% (R² = .628). ICC = 0.387 indicated that 38.7% of variance was attributed to random effects. A significant group effect ( F (2, 183.82) = 5.64, p = .004) showed that cognitive fusion was highest in the control group, significantly exceeding levels in both asynchronous ( p < .001) and synchronous ( p < .001) groups. No differences were found between the two intervention groups ( p = 1.000). A main effect of time was also significant ( F (2, 203.72) = 55.25, p < .001), indicating a progressive decline in cognitive fusion over repeated measurements (all p < .001). A significant interaction ( F (3, 202.61) = 14.46, p < .001) revealed that cognitive fusion remained stable in the control group, while both intervention groups experienced a significant reduction between the first and later assessments. No group differences emerged at baseline ( p = .705) or the final measurement ( p = .516), but fusion levels in the control group were significantly higher at the second time point compared to the intervention groups ( p < 0.001). No difference was detected between synchronous and asynchronous conditions ( p = 1.000). 2.1.5 Resilience The model was evaluated using BIC = 2623.38. Fixed effects explained 12.7% of variance (R² = .127), while total variance explained was 74.9% (R² = .749). ICC = .622 indicated that 62.2% of variance was attributable to random effects. A significant group effect ( F (2, 173.89) = 4.05, p = .019) showed that psychological resilience was lower in the control group compared to both asynchronous ( p = .004) and synchronous ( p = .003) groups, with no significant difference between intervention groups ( p = 1.000). A significant time effect ( F (2, 176.77) = 41.55, p < .001) indicated a progressive increase in resilience across measurements (all p < .001). A significant interaction ( F (3, 176.44) = 5.80, p < .001) revealed that resilience remained stable in the control group, whereas both intervention groups showed a significant increase from the first to later measurements, with no difference between the second and third time points. No group differences were observed at baseline ( p = .558) or in the final measurement ( p = .855), but the control group had lower resilience levels at the second time point compared to both intervention groups ( p < .001). No difference was found between synchronous and asynchronous groups ( p = 1.000). 2.1.6 Experiential Avoidance For BA, the model (BIC = 1963.25) explained 3.0% of variance through fixed effects (R² = .030), while total variance explained was 58.9% (R² = .589). ICC = .559 indicated that 55.9% of variance was due to individual differences. The group effect was not significant ( p = .236), with comparable BA levels across groups. A small but significant time effect ( p = .029) showed a decrease in BA from the first to the third measurement, while the interaction was non-significant ( p = .548). Regression analysis confirmed that the only significant effect was the reduction in BA over time. For CEA, a separate model (BIC = 2133.07) explained 20.4% of variance through fixed effects (R² = .204), with total variance explained at 65.4% (R² = 0.654). ICC = .449 suggested that 44.9% of variance was due to individual differences. A significant group effect ( p < .001) indicated that CEA was higher in the control group than in both intervention groups ( p < .001), with no difference between the asynchronous and synchronous groups ( p = .285). A significant time effect ( p < .001) demonstrated a progressive decline in CEA across all measurements. A significant interaction effect ( p < .001) showed that CEA remained stable in the control group between the first and second measurements ( p = .209), while both intervention groups experienced a significant reduction from the first to later time points ( p < .001), with no further change between the second and third measurements. No significant differences were found at baseline ( p = .293) or the final measurement ( p = .267). However, at the second measurement, CEA was significantly higher in the control group compared to both intervention groups ( p < .001), with no difference between the synchronous and asynchronous groups ( p = .471). 2.1.7 Mindfulness The model was evaluated using BIC = 2587.46. Fixed effects accounted for 28.0% of the variance (R² = .280), while the total explained variance was 68.8% (R² = .688). The intraclass correlation coefficient (ICC = .408) indicated that 40.8% of the variance was attributable to individual differences. A significant group effect ( F (2, 186.21) = 6.95, p = .001) showed that mindfulness levels were lower in the control group compared to the asynchronous ( p < .001) and synchronous ( p < .001) groups, with no significant difference between the two intervention groups ( p = 1.000). A significant time effect ( F (2, 199.10) = 81.84, p < .001) indicated a steady increase in mindfulness over time (all p < .001), with mean FFMQ scores rising from 69.87 at baseline to 80.04 at the second measurement and 87.69 at the third measurement. A significant interaction effect (F(3, 198.18) = 16.95, p < .001) revealed that mindfulness remained stable in the control group between the first and second assessments ( p = .456), whereas both intervention groups showed a significant increase from the first to subsequent measurements ( p < .001), with no further improvement between the second and third time points. No significant differences were found between groups at baseline ( p = .406) or at the final assessment ( p = .311). However, at the second measurement, mindfulness levels in the control group were significantly lower than in both intervention groups ( p < .001). No differences were detected between the synchronous and asynchronous groups ( p = .750). 2.1.8 Rumination The model was evaluated using BIC = 2496.07. Fixed effects explained 17.4% of variance (R² = 0.174), while total variance explained was 56.0% (R² = 0.560). ICC = 0.386 indicated that 38.6% of variance was attributable to individual differences. The group effect was not significant ( p = .099), but post hoc comparisons revealed that rumination was higher in the control group than in the asynchronous group ( p = .005), while the synchronous group did not differ significantly from either. A significant time effect ( p < .001) indicated a progressive decline in rumination across assessments (all p < .001), with no significant difference between the second and third measurements ( p = .088). A significant interaction effect ( p < .001) showed that rumination levels remained stable in the control group between the first and second assessments ( p = .222), whereas both intervention groups exhibited a significant decrease between the first and later time points ( p < .001), with no further decline between the second and third measurements. No differences were found at baseline ( p = .440), but at the second measurement, rumination was significantly higher in the control group compared to the asynchronous group ( p = .002). By the third measurement, the synchronous group had significantly higher rumination than the asynchronous group ( p = .019). 2.1.9 Self-compassion The model was evaluated using BIC = 2239.97. Fixed effects explained 16.8% of variance (R² = .168), while total variance explained was 45.5% (R² = .455). ICC = .287 indicated that 28.7% of variance was due to individual differences. The group effect was not significant ( p = .066), but post hoc analysis showed that self-compassion was lower in the control group compared to both the asynchronous ( p = .030) and synchronous groups ( p = .007), with no difference between the intervention groups ( p = .000). A significant time effect ( p < .001) indicated a gradual increase in self-compassion across assessments, with no difference between the second and third measurements ( p = .227). A significant interaction effect ( p < .001) showed that self-compassion remained stable in the control group between the first and second assessments ( p = .490), while both intervention groups exhibited a significant increase from the first to later measurements ( p < .001), with no further difference between the second and third time points. No differences were found at baseline ( p = .139) or at the final measurement ( p = .120). However, at the second measurement, self-compassion was significantly lower in the control group compared to the asynchronous ( p < .001) and synchronous groups ( p = .003), with no significant difference between the intervention groups ( p = .291). 2.2 Mechanisms of change Out of 21 examined models (Appendix), the best characteristic had mindfulness and cognitive fusion (measured at the second time point) as mediators of the relationship between group membership and depression severity (CESD score at the second time point). FFMQ, CFQ, and CESD from the first measurement were included as control variables. The analysis revealed a significant relationship between group membership and mindfulness (β = .93, p < .001), as well as between group membership and cognitive fusion (β = − .95, p < .001). Participants in the interventions group reported higher mindfulness and lower cognitive fusion than those in the control group. Mindfulness was negatively associated with depression severity when controlling for group membership and baseline values (β = − .30, p = .001), indicating that higher mindfulness levels corresponded with lower depression severity. Conversely, cognitive fusion was positively associated with depression severity (β = .35, p < .001), meaning higher fusion levels were linked to increased depression symptoms. After accounting for mediators, the direct effect of group membership on depression remained significant and negative (β = -0.30, p = .049). Mediation analysis confirmed a significant total indirect effect (b = -6.52; 95% CI [-9.25, -4.32]), with both mindfulness (b = -2.98; 95% CI [-5.46, -0.82]) and cognitive fusion (b = -3.54; 95% CI [-6.05, -1.65]) acting as significant mediators. The findings support partial mediation, as the direct effect between group membership and depression remained significant after accounting for mediators. This highlights the crucial role of mindfulness and cognitive fusion in explaining the relationship between group membership and depression severity. Table 7 Summary of mediation model for the relationship between group membership and depression severity (CESD) CI 95% Model Effect a B SE β t p LL UL R 2 Model 1 M1: FFMQ M2: CFQ a1 13.21 1.86 0.93 7,10 < 0,001 9.53 16.90 a2 -7.86 1.15 -0.95 -6,84 < 0,001 -10.14 -5.59 b1 -0.23 0.06 -0.30 -3,50 0,001 -0.35 -0.10 b2 0.45 0.11 0.35 4,05 < 0,001 0.23 0.67 c’ -3.16 1.59 -0.30 -1,98 0,049 -6.31 -0.01 0.52 c -9.68 1.63 -12.89 -6.45 c – c’ -6.52 1.24 -0.62 -9.25 -4.32 FFMQ -2.98 1.18 -0.28 -5.46 -0.82 CFQ -3.54 1.12 -0.34 -6.05 -1.65 Note . In each model, the independent variable is group membership, while the dependent variable is depression severity (CESD score). a c – c’ represents the total indirect effect, testing the mediation effect with both mediators included. If the confidence intervals do not contain zero, the mediation effect is statistically significant at p < 0.05. CFQ – Cognitive Fusion; FFMQ – Mindfulness 2.3 Negative effects After the intervention, 76 participants completed the Negative Effects Questionnaire (NEQ). To assess the overall intensity of negative effects, a mean NEQ score was calculated for each participant. The average NEQ score was 0.28 (SD = .36), with a minimum of 0.00, a maximum of 1.65, and a mode of 0.18. The mean number of summed negative effect items per participant was 5.58 (SD = 7.12), ranging from 0 to 33. Fourteen participants (17%) reported no negative effects, while the remaining 83% reported experiencing at least one negative effect during the intervention. For 75% of participants, the impact of negative effects ranged from experiencing multiple symptoms with minimal impact (up to 7 symptoms) to experiencing fewer symptoms (around 2) with strong or extreme impact. The most frequently reported negative effects were: increased levels of stress (n = 24, mean impact = 1.7), greater worry (n = 20, mean impact = 1.3), more frequent unpleasant feelings (n = 20, mean impact = 1.8), recurring unpleasant memories (n = 24, mean impact = 1.54). 2.4 Treatment response In a study on clinical significance and depression assessment tools, Kounali et al. ( 2022 ) found that a 20% reduction in the total questionnaire score can be classified as a minimal clinically important difference (MCID). Therefore, in the present study, a 20% reduction was used as the cutoff for "improvement." Scores between 0% and 20% were categorized as "no change," while an increased severity of symptoms was classified as "deterioration." Among the 77 participants who completed the post-test CES-D measurement, 62 (81%) met the criteria for a clinically significant treatment response, scoring more than 20% lower on the depression scale compared to their pre-intervention scores. The mean improvement was 44%, with a median of 51%. Table 8 presents detailed data, stratified by the asynchronous and synchronous groups. Table 8 Deterioration No change Improvement Mean improvement Median Min Max Asynchronous 3 (9%) 2 (6%) 29 (85%) 51%(SD = 35) 55% -57% 98% Synchronous 4 (9%) 6 (14%) 33 (77%) 39%(SD = 32) 45% -52% 92% 2.5 Engagement Participants' activity on the platform was tracked based on login counts and time spent on audio recordings. However, data from the synchronous group were excluded from analysis, as mindfulness instructors allowed to use for guided meditation recordings their own websites, YouTube channels, or MP3 files they provided – what could not be controlled. In the asynchronous group, the mean time spent on recordings was 611 minutes (SD = 411), with a minimum of 33 minutes and a maximum of 1,715 minutes (approximately 28 hours). The mean number of logins was 100 (SD = 83; min: 15, max: 457) in the asynchronous and 101 (SD = 92; min = 91 and max = 405) in synchronous group. Table 9 Engagement metrics: session count and time spent by synchronous vs. asynchronous groups Mean time Min time Max time Mean session number Min Max Asynchronous 611 (SD = 411) 33 1715 100(SD = 83) 15 457 Synchronous 327 (SD = 543) 0 2771 101(SD = 92) 11 405 Note. Time refers to the duration spent on recordings, not total time on the platform. 2.6 Attrition Out of 170 participants randomized into three conditions, 125 (74%) completed the posttest assessment. Attrition rates varied across groups: 28% in the synchronous group, 45% in the asynchronous group, and 4% in the control group. Participants who remained inactive for more than five days received automated emails containing psychoeducational content and encouragement to re-engage with the program. However, those who did not respond to these emails or remained inactive for over three weeks were classified as dropouts. Upon logging into the platform, they were presented with a pop-up requesting feedback on their reasons for discontinuation. After the three months, in the follow-up, the attrition was 59% in the asynchronous and 66% in synchronous condition. As a total of 45 participants did not complete the posttest, the amount of collected feedback was limited. The reported reasons for dropout included: Perceiving the program as too intense or experiencing frustration due to an inability to complete all tasks (n = 4), finding another solution that better suited their needs (n = 1), deciding to seek psychiatric consultation instead (n = 1) No statistically significant differences were found between completers and non-completers on any of the baseline variables, either in the full sample or within the separate intervention conditions (all ps > .05). This included demographic factors (e.g., gender, education) as well as psychological variables such as baseline levels of depression, anxiety, mindfulness. Although a few comparisons approached significance (e.g., rumination and gender in the synchronous group), all effect sizes were small to moderate and non-significant. These findings suggest that dropout was not associated with specific participant characteristics. 2.7 The perception of the program At the end of the posttest, participants were asked to rate the extent to which the program met their expectations on a scale from 0 to 4, with an option to provide additional comments. Of the 62 respondents (81% response rate), the average rating was 3.16 (SD = .61). The highest rating, 4 ("definitively yes"), was selected by 17 participants, while the lowest, 2 ("hard to say"), was chosen by 7 participants. Among those least satisfied, elaborated responses highlighted concerns such as the large number of exercises and the irritating need for sustained focus during exercises (n = 2), frustration with the difficulty of establishing a habit and maintaining regular practice (n = 2), and challenges in translating mindfulness knowledge and skills into self-efficacy (n = 1). Conversely, among participants whose expectations were met, the most common themes in their comments included noticeable improvements in mood and stress reduction (n = 12), increased self-awareness and new insights (n = 6), and perceived benefits of the program (n = 6). Additional comments (n = 9) covered recommendations for the researchers and reflections on the challenges of mindfulness practice. 4. Discussion The aim of the study was to evaluate the effectiveness of an online Mindfulness-Based Cognitive Therapy intervention in individuals experiencing depression, and to compare two delivery formats - online group synchronous MBCT and guided asynchronous iMBCT. Furthermore to identify key mechanisms of change. Results indicated that both intervention formats led to significant improvements across all measured outcomes, including depressive symptoms, resilience, self-compassion, rumination, cognitive fusion, experiential avoidance, and mindfulness. Notably, there were no significant differences between the synchronous and asynchronous conditions at posttest or follow-up, suggesting that both delivery formats may be comparably effective in reducing psychopathological symptoms and enhancing self-regulation. These findings are consistent with prior studies demonstrating the effectiveness of iMBCT in reducing symptoms of anxiety and depression (Holas & Wardęszkiewicz, under review; Liu et al., 2024 ; Rodrigues et al., 2024 ; Nissen et al., 2020 ; Segal et al., 2020 , Boettcher et al., 2014 ), and in promoting resilience (Holas & Wardęszkiewicz, 2025. Moreover, the results align with the theoretical framework of MBCT, which posits that cultivating mindfulness - defined as nonjudgmental awareness of the present-moment (Kabat-Zinn, 2015 ) - interrupts maladaptive cognitive and emotional patterns such as rumination and cognitive fusion (Foroughi et al., 2020). By fostering the ability to observe thoughts and feelings as passing mental events, rather than identifying with them (Teasdale et al., 2002 ), mindfulness is theorized to reduce the risk of depressive relapse (Segal et al., 2012 ). Supporting this model, the present study identified mindfulness and cognitive fusion as the most robust mediators of treatment response. Similar findings were reported by Dimidjian and collaborators (2023), who observed that improvements following online MBCT were mediated by decentering, mindfulness, and reductions in rumination. Notably, improvement in cognitive defusion was observed despite the absence of the specific session typically dedicated to this concept in standard MBCT (“Thoughts are not facts”). This finding suggests that the capacity to relate to thoughts in a decentered way may develop more broadly throughout the MBCT training, even in its abbreviated format. Despite the comparable efficacy across conditions, notable differences in attrition emerged between the two online abbreviated MBCT formats. Specifically, 45% of participants in the asynchronous condition discontinued the intervention prior to the posttest, compared to 28% in the synchronous group. These figures are within the range observed in previous online MBIs, where dropout rates have varied from 8–65% (Spijkerman et al., 2021) and from 2.5–57%, with a mean of 25.8% (SD = 17.1) in another meta-analysis (Reangsing et al., 2023 ). While no prior study has directly compared synchronous and asynchronous mindfulness-based interventions for depression, findings from broader online intervention literature consistently show that synchronous formats - characterized by real-time interaction and therapist guidance - are associated with greater adherence (Mammarella et al., 2024 ; Andersson & Titov, 2014 ). In contrast, asynchronous formats often show higher attrition, likely due to limited support and a lack of immediate feedback (Wolever et al., 2022 ). Nonetheless, asynchronous delivery offers important advantages, including time flexibility, scalability, and lower operational demands (Andersson & Titov, 2014 ). Given the comparable symptom reduction observed in both formats, the question may no longer be which format is superior in effectiveness, but rather how to optimize user engagement and minimize dropout, particularly in less guided interventions. Future studies should focus on developing and testing strategies to enhance adherence in asynchronous interventions, such as reminders, chatbot-guidance, or hybrid formats. The findings suggest that structured, evidence-based programs like iMBCT - whether delivered synchronously or asynchronously - may serve as accessible, low-threshold interventions for the depressed population. In real-world healthcare, such interventions could be recommended following psychiatric consultations in less severe cases or offered as a meaningful form of support during waiting periods for in-person psychotherapy. Promoting early access to online interventions targeting self-regulation and mindfulness could help prevent symptom escalation and reduce long-term treatment needs. 3.1 Limitations One limitation of this study is that not all components of the intervention were delivered within a single, integrated study platform. While participants in the asynchronous condition completed the entire program within the platform, those in the synchronous condition attended live sessions via external tools such as Zoom or Google Meet. Additionally, mindfulness instructors provided external resources for guided meditation practice (e.g., personal websites or YouTube links). Under these circumstances, it was not possible to comprehensively track participant engagement in the synchronous condition. A second limitation concerns the use of a waiting-list control group rather than an active comparator. Although a waitlist design controls for some nonspecific factors, such as the passage of time, it may overestimate treatment effects and does not reflect real-life behavior, where individuals often search for alternative forms of support while waiting (Freedland et al., 2011 ; Cunningham et al., 2013 ). Moreover, the absence of a follow-up assessment in the control group limits the ability to compare long-term outcomes across all conditions. However, requiring participants with depression to remain without access to intervention for over four months was considered ethically inappropriate. Future studies should consider including an active control, such as treatment-as-usual (TAU) with a follow-up assessment. Another limitation involves the demographic homogeneity of the sample, which was predominantly female and well-educated. This overrepresentation is typical in mindfulness-based intervention research, where women often account for more than 70% of participants (Eichel et al., 2021 ). However, it restricts the generalizability of the findings. Future research should prioritize the inclusion of more diverse populations to better understand the applicability and impact of iMBCT across sociodemographic groups. All outcomes in this study were assessed via self-report questionnaires. While the MINI was used for diagnostic screening during recruitment, the absence of clinician-rated or behavioral outcome measures may introduce biases. Incorporating objective assessments in future trials would enhance the validity of the findings. Finally, the intervention was a shortened adaptation of the standard 8-week MBCT protocol, delivered over six weeks. Although the content remained consistent with MBCT’s core structure, the shortened duration may have limited the opportunity for skill consolidation or depth of practice. Future research should explore the comparative effectiveness of full-length and brief MBCT formats to better understand how modifications impact outcomes and adherence. 3.2 Future directions Building on the present findings, future research could explore the effectiveness of various engagement strategies - such as incorporating chatbots or blending design with other forms of real-time feedback - to improve adherence in asynchronous formats. Efforts to recruit more diverse samples, particularly with regard to gender, education level, and digital literacy, would also help address current limitations in generalizability. Additionally, studying the impact of intervention length may offer valuable insights, as online MBIs vary widely in duration, typically ranging from 2 to 12 weeks (Spijkerman et al., 2016 ). Understanding how program length influences both adherence and perceived effectiveness could help optimize delivery for different populations. Future research could also explore individual characteristics that predict greater benefit from one delivery format over another, including factors such as self-discipline, motivation, attitudes towards psychological online interventions or confidence in therapy effectiveness. 3.3 Conclusion The present study demonstrated that both synchronous group and asynchronous formats of iMBCT may serve as effective interventions for individuals experiencing mild to moderate depressive symptoms. While the synchronous format was associated with higher completion rates, the asynchronous format offers greater time flexibility and showed comparable effects in reducing depression and anxiety, as well as enhancing resilience, self-compassion, mindfulness, and cognitive defusion. 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(2015). Using Mindfulness-Based Cognitive Therapy in Individual Counseling to Reduce Stress and Increase Mindfulness: An Exploratory Study With Nursing Students. Professional Counselor, 5(1). Taylor, H., Strauss, C., & Cavanagh, K. (2021). Can a little bit of mindfulness do you good? A systematic review and meta-analyses of unguided mindfulness-based self-help interventions. Clinical Psychology Review, 89, 102078. https://doi.org/10.1016/j.cpr.2021.102078 Teasdale, J. D., Segal, Z. V., Williams, J. M. G., Ridgeway, V. A., Soulsby, J. M., & Lau, M. A. (2000). Prevention of relapse/recurrence in major depression by mindfulness-based cognitive therapy. Journal of Consulting and Clinical Psychology, 68(4), 615–623. https://doi.org/10.1037/0022-006X.68.4.615 Teasdale, J. D., Moore, R. G., Hayhurst, H., Pope, M., Williams, S., & Segal, Z. V. (2002). Metacognitive awareness and prevention of relapse in depression: empirical evidence. 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M., Helpman, L., Mootz, J. J., Johnson, K. A., ... & Arbuckle, M. R. (2017). Challenges and opportunities in global mental health: A research-to-practice perspective. Current Psychiatry Reports, 19(5), 28. https://doi.org/10.1007/s11920-017-0780-z Wang, P. S., Beck, A. L., Berglund, P., McKenas, D. K., Pronk, N. P., Simon, G. E., & Kessler, R. C. (2004). Effects of major depression on moment-in-time work performance. American Journal of Psychiatry, 161(10), 1885–1891. https://doi.org/10.1176/appi.ajp.161.10.1885 Wang, Q., Zhang, W., & An, S. (2023). A systematic review and meta-analysis of internet-based self-help interventions for mental health among adolescents and college students. Internet Interventions, 100690. https://doi.org/10.1016/j.invent.2023.100690 Wang, Z., Shalihaer, K., Hofmann, S. G., Feng, S., & Liu, X. (2024). The role of attentional control in mindfulness intervention for emotional distress: A randomized controlled trial with longitudinal mediation analyses. Clinical Psychology & Psychotherapy, 31(3), e2981. https://doi.org/10.1002/cpp.2981 Wolever, R. Q., Finn, M. T., & Shields, D. (2022). The relative contributions of live and recorded online mindfulness training programs to lower stress in the workplace: Longitudinal observational study. Journal of Medical Internet Research, 24(1), e31935. https://doi.org/10.2196/31935 World Health Organization. (2022). World mental health report: Transforming mental health for all. World Health Organization. https://www.who.int/publications/i/item/9789240050860 World Health Organization. (2023). Depression. World Health Organization. Retrieved [01.02.2025], from https://www.who.int/news-room/fact-sheets/detail/depression Zhang, D., Lee, E. K., Mak, E. C., Ho, C. Y., & Wong, S. Y. (2021). Mindfulness-based interventions: An overall review. British Medical Bulletin, 138(1), 41–57. https://doi.org/10.1093/bmb/ldab005 Table numbering Table numbers 3 and 4 are not used in this version. 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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-7166236","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":487913081,"identity":"ace8bc6c-5a58-4fa3-81dc-1a48b8395475","order_by":0,"name":"Jan Wardęszkiewicz","email":"data:image/png;base64,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","orcid":"https://orcid.org/0000-0002-6152-2844","institution":"Faculty of Psychology, University of Warsaw","correspondingAuthor":true,"prefix":"","firstName":"Jan","middleName":"","lastName":"Wardęszkiewicz","suffix":""},{"id":487913082,"identity":"ed36692d-655c-4d05-8f76-616ee6930113","order_by":1,"name":"Paweł Holas","email":"","orcid":"https://orcid.org/0000-0002-4210-3396","institution":"Faculty of Psychology, University of Warsaw","correspondingAuthor":false,"prefix":"","firstName":"Paweł","middleName":"","lastName":"Holas","suffix":""},{"id":487913083,"identity":"a24993b5-4883-422b-9772-13db42643260","order_by":2,"name":"Gerhard Andersson","email":"","orcid":"https://orcid.org/0000-0003-4753-6745","institution":"Department of Behavioural Sciences and Learning, Department of Biomedical and Clinical Sciences, Linköping University","correspondingAuthor":false,"prefix":"","firstName":"Gerhard","middleName":"","lastName":"Andersson","suffix":""}],"badges":[],"createdAt":"2025-07-19 19:09:07","currentVersionCode":1,"declarations":{"humanSubjects":true,"vertebrateSubjects":false,"conflictsOfInterestStatement":false,"humanSubjectEthicalGuidelines":true,"humanSubjectConsent":true,"humanSubjectClinicalTrial":true,"humanSubjectCaseReport":false,"vertebrateSubjectEthicalGuidelines":false},"doi":"10.21203/rs.3.rs-7166236/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7166236/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":87824153,"identity":"fbba62c3-9e42-4f75-b225-e1618a70a935","added_by":"auto","created_at":"2025-07-29 11:34:01","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":627742,"visible":true,"origin":"","legend":"\u003cp\u003eLegend not included with this version\u003c/p\u003e","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7166236/v1/0fb305bd2c711f8320ef678f.jpeg"},{"id":87875385,"identity":"97a16947-d8a2-4914-9c95-0f7be55e0214","added_by":"auto","created_at":"2025-07-30 02:11:21","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1987569,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7166236/v1/68cfd6ba-b315-4221-995c-6f78e9bc61c1.pdf"}],"financialInterests":"The authors declare no competing interests.","formattedTitle":"\u003cp\u003e\u003cstrong\u003eSynchronous online group MBCT vs guided asynchronous iMBCT in depressed sample: randomized clinical trial with a 3-month follow-up\u003c/strong\u003e\u003c/p\u003e","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eDepression is a prevalent mental health disorder, affecting approximately 5% of adults worldwide (World Health Organization, \u003cspan citationid=\"CR83\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Individuals experiencing depression commonly report a range of emotional distress, including feelings of guilt, worthlessness, and hopelessness, as well as sleep disturbances, changes in appetite, and persistent low mood (Radloff, \u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e1977\u003c/span\u003e). Beyond these symptoms, depression disrupts multiple aspects of functioning, including cognitive (Baune \u0026amp; Air, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2016\u003c/span\u003e), social (Steger \u0026amp; Kashdan, \u003cspan citationid=\"CR69\" class=\"CitationRef\"\u003e2009\u003c/span\u003e), biological (Cui et al., \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2024\u003c/span\u003e; Nestler et al., \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2002\u003c/span\u003e), psychological (Beck et al., \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e1993\u003c/span\u003e; Maier \u0026amp; Seligman, \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e1976\u003c/span\u003e), and occupational domains (Wang et al., \u003cspan citationid=\"CR78\" class=\"CitationRef\"\u003e2004\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eDespite the documented efficacy of evidence-based psychotherapies and pharmacological treatments, access to mental health care remains critically limited worldwide (Wainberg et al., \u003cspan citationid=\"CR77\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). A global analysis of the treatment gap between 2000 and 2019 revealed that the proportion of individuals receiving minimally adequate treatment for depression ranged from just 3% in low-income countries to 23% in high-income countries (Moitra et al., \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). This persistent disparity is multifaceted and can be attributed to several factors, including the limited availability of trained specialists, the high cost of treatment, geographical barriers to accessing services, and the persistent stigma surrounding mental disorders (World Health Organization, \u003cspan citationid=\"CR82\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). Given these challenges, there is an urgent need to explore scalable alternatives that can bridge this gap and expand access to mental health care.\u003c/p\u003e\u003cdiv id=\"Sec2\" class=\"Section2\"\u003e\u003ch2\u003e1.1 Internet-based psychological interventions\u003c/h2\u003e\u003cp\u003eOne promising approach is internet-based psychological interventions, which offer a cost-effective and scalable solution to mental health service delivery (Schueller \u0026amp; Torous, \u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). These interventions have demonstrated satisfactory effectiveness in treating mental health disorders, as evidenced by numerous meta-analyses (Guo et al., \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Fischer-Grote et al., \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2024\u003c/span\u003e; Wang et al., \u003cspan citationid=\"CR79\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Pauley et al., \u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e2023\u003c/span\u003e), including depression (Moshe et al., \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Karyotaki et al., \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). However, despite their growing empirical support, more research is still needed to ensure their safe and effective integration into routine primary care (Smith et al., \u003cspan citationid=\"CR64\" class=\"CitationRef\"\u003e2023\u003c/span\u003e).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003e1.2 Online mindfulness-based interventions\u003c/h2\u003e\u003cp\u003eAmong the various internet-based psychological interventions, online mindfulness-based interventions (MBIs) have been increasingly studied as a promising approach for reducing depressive symptoms (meta-analyses: Sommers-Spijkerman et al., \u003cspan citationid=\"CR67\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Spijkerman et al., \u003cspan citationid=\"CR68\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). Research indicates that in-person mindfulness interventions target key cognitive and emotional mechanisms that contribute to the persistence of depression, including rumination (Li et al., \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2022\u003c/span\u003e), worry (van der Velden et al., \u003cspan citationid=\"CR76\" class=\"CitationRef\"\u003e2015\u003c/span\u003e), and repetitive negative thinking (MacKenzie et al., \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). Additionally, MBIs have been associated with improvements in self-regulation (Wang et al., \u003cspan citationid=\"CR80\" class=\"CitationRef\"\u003e2024\u003c/span\u003e), self-compassion (Ha \u0026amp; Kim, 2023), and resilience (P\u0026eacute;rez-Aranda et al., \u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e2021\u003c/span\u003e), all of which contribute to the reduction of depressive symptoms. While a significant body of research has examined these mechanisms within in-person programs, further studies are needed to determine whether online adaptations effectively engage the same processes.\u003c/p\u003e\u003cp\u003eAs research on online MBIs has expanded exponentially (Ferreira \u0026amp; Demarzo, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2024\u003c/span\u003e), challenges related to standardized reporting have become increasingly evident (Wolever et al., \u003cspan citationid=\"CR81\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). The term 'online intervention' encompasses a wide range of delivery methods, including guided and unguided formats, synchronous and asynchronous sessions, as well as mobile- and web-based platforms (Smoktunowicz et al., \u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e2020\u003c/span\u003e), making consistent classification and comparison difficult. These distinctions are crucial, as delivery format appears to influence intervention outcomes. For example, one study found that an online (synchronous) MBIs had a greater impact on stress reduction compared to an unguided, asynchronous program (Wolever et al., \u003cspan citationid=\"CR81\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). A meta-analysis by Taylor et al. (\u003cspan citationid=\"CR71\" class=\"CitationRef\"\u003e2021\u003c/span\u003e) suggested that unguided MBIs had a smaller effect on depression, mindfulness, and quality of life compared to non-digital unguided interventions (e.g., textbook and CD-based programs). Furthermore, these variations refer only to the technical aspects of intervention delivery, without accounting for substantial differences in content, duration, therapeutic approach, or symptom measurement/diagnosis methods, all of which may further influence intervention efficacy. To address these issues there is an agreement that more good quality randomized controlled trials (RCTs) are needed, comparing different online MBIs formats (Taylor et al., \u003cspan citationid=\"CR71\" class=\"CitationRef\"\u003e2021\u003c/span\u003e), such as synchronous and asynchronous (Toivonen et al., \u003cspan citationid=\"CR74\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Schwarze \u0026amp; Gerler, \u003cspan citationid=\"CR70\" class=\"CitationRef\"\u003e2015\u003c/span\u003e) or reaching specific clinical populations (Sevilla-Llewellyn-Jones et al., \u003cspan citationid=\"CR60\" class=\"CitationRef\"\u003e2018\u003c/span\u003e).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\u003ch2\u003e1.3 Online Mindfulness-Based Cognitive Therapy\u003c/h2\u003e\u003cp\u003eMindfulness-Based Cognitive Therapy (MBCT) is one of the most extensively studied MBIs (Zhang et al., \u003cspan citationid=\"CR84\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). This is an 8-week program consisting of weekly group sessions lasting 2 to 2.5 hours. The course integrates formal mindfulness practices, including the body scan, sitting meditation, and mindful movement, with cognitive-behavioral therapy components such as psychoeducation on depression or behavioral activation (Sipe \u0026amp; Eisendrath, \u003cspan citationid=\"CR63\" class=\"CitationRef\"\u003e2012\u003c/span\u003e). Originally developed to prevent relapse in recurrent depression (Teasdale et al. \u003cspan citationid=\"CR72\" class=\"CitationRef\"\u003e2000\u003c/span\u003e), MBCT has demonstrated effectiveness in this area, as supported by meta-analyses (Piet \u0026amp; Hougaard, \u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e2011\u003c/span\u003e; Kuyken, et al., \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2016\u003c/span\u003e; McCartney et al., \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). However, research also indicates its efficacy in treating current depressive episodes (meta-analyses: Goldberg et al., \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Tseng et al., \u003cspan citationid=\"CR75\" class=\"CitationRef\"\u003e2023\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eWhile MBCT is well established in face-to-face settings, its online adaptation (iMBCT) has thus far demonstrated only preliminary evidence of effectiveness in reducing stress (Dowd et al., \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2015\u003c/span\u003e), emotional distress (Cillessen et al., \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; Holas \u0026amp; Wardęszkiewicz, under review), and symptoms of anxiety and depression (Nissen et al., \u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Segal et al., \u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Seritan et al., \u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). However, no study to date has directly compared the effectiveness of different iMBCT delivery formats in treating depression.\u003c/p\u003e\u003cp\u003ePrior research suggests that guided psychological interventions are associated with higher adherence and greater symptom reduction than unguided approaches (Berger et al., \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2011\u003c/span\u003e), including within online mindfulness interventions (Wolever et al., \u003cspan citationid=\"CR81\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). While both synchronous and asynchronous iMBCT formats can include guidance, they differ substantially in the mode and immediacy of therapist interaction - potentially affecting engagement and outcomes. Notably, asynchronous iMBCT has been associated with higher attrition rates (Holas \u0026amp; Wardęszkiewicz, under review), suggesting the delivery format itself may play a critical role. Despite these concerns, no study has directly compared synchronous and asynchronous iMBCT in individuals with major depressive disorder, leaving an important gap in understanding the impact of delivery method on treatment effectiveness and adherence.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\u003ch2\u003e1.3 Present study\u003c/h2\u003e\u003cp\u003eThe present study aims to evaluate the effectiveness of an online adaptation of MBCT in both synchronous and asynchronous formats in a sample of individuals with depression. Given the high heterogeneity of online MBI formats, which poses a persistent challenge for meta-analytic synthesis (Gong et al., \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2023\u003c/span\u003e), it is crucial to also investigate existing, structured and standardized interventions in parallel with the development and evaluation of new approaches. Additionally, as the depressed population is particularly vulnerable, selecting a well-established, evidence-based intervention is essential. Among MBIs, MBCT stands out as one of the most rigorously studied and empirically supported programs, particularly for clinical populations (Zhang et al., \u003cspan citationid=\"CR84\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). Unlike other online MBIs, which vary in structure and theoretical underpinnings, MBCT is a manualized program with well-defined protocols, making it a logical candidate for digital adaptation and larger-scale implementation. Despite this, research on iMBCT remains limited, particularly in individuals with clinical depression. As the debate regarding the most optimal delivery format remains unresolved, further high-quality RCTs are needed to clarify their comparative effectiveness. To address this gap, participants in the present study were planned to be randomly assigned to either online synchronous group MBCT or asynchronous iMBCT, with a waiting-list control group serving as a comparator.\u003c/p\u003e\u003c/div\u003e"},{"header":"2. Methods","content":"\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\u003ch2\u003e2.1 Design\u003c/h2\u003e\u003cp\u003eIn the present study, our objective was to assess the efficacy and mechanisms of change associated with the online, six-week Mindfulness-Based Cognitive Therapy (MBCT) intervention for individuals with mild-to-moderate depression. The study employed a three-arm design, comprising an asynchronous guided group iMBCT, an online synchronous group iMBCT, and a control group assigned to a waiting list. Despite the completion of pre-test and post-test questionnaires, participants were asked to complete a follow-up assessment after a three-month interval. The study was approved by the Ethics Committee of the Psychology Faculty of the University of Warsaw (NR:11/04/2023) and registered in the Clinical Trial Register (NCT05919875).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003e2.2 Participants\u003c/h2\u003e\u003cp\u003eParticipants were recruited through the Internet. The advertisements were primarily posted on social media platforms and were widely shared due to the voluntary participation of individuals who expressed appreciation for the project. Additionally, information about the study was published on university websites or included in newsletters.\u003c/p\u003e\u003cp\u003eThe advertisements specified that the project was intended for adults experiencing significant deterioration in psychological functioning who wished to develop or improve self-regulation skills. The landing page explicitly stated that individuals experiencing severe depressive episodes, in crisis, diagnosed with psychotic or bipolar disorders, or currently undergoing psychotherapy were ineligible to participate.\u003c/p\u003e\u003cp\u003eA total of 502 individuals registered on the platform, of whom 444 completed all required questionnaires. Of these, 117 were excluded due to ongoing psychotherapy, 33 did not exhibit depressive symptoms, and 12 reported severe depression and were referred to psychological support centers. Among the 282 structured interviews conducted, 198 participants met the inclusion criteria; however, 28 did not complete all required questionnaires. Ultimately, 170 participants were randomized into one of three conditions: the synchronous iMBCT group (n\u0026thinsp;=\u0026thinsp;58), the asynchronous iMBCT group (n\u0026thinsp;=\u0026thinsp;59), or the waitlist control group (WLC; n\u0026thinsp;=\u0026thinsp;53). Characteristics of the sample are shown in Table\u0026nbsp;1 and Flow chart 1.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Taba\" border=\"1\"\u003e\u003ccolgroup cols=\"4\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colspan=\"3\" nameend=\"c3\" namest=\"c1\"\u003e\u003cp\u003eTable\u0026nbsp;1. \u003cem\u003eSociodemographic characteristic of the sample\u003c/em\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eiMBCT synchronous (n\u0026thinsp;=\u0026thinsp;58)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eiMBCT asynchronous (n\u0026thinsp;=\u0026thinsp;59)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eWLC\u003c/p\u003e\u003cp\u003e(n\u0026thinsp;=\u0026thinsp;53)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMan\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e13\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e7\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eWoman\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e45\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e46\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMean age\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e3\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003e9\u003c/span\u003e,5 (SD\u0026thinsp;=\u0026thinsp;10)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e36 (SD\u0026thinsp;=\u0026thinsp;10.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e37(SD\u0026thinsp;=\u0026thinsp;10)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eHigher education\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e48\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e47\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e46\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSecondary education\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eElementary education\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eStudying\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMetropolitan city\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e26\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e28\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e24\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eLarge city\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e13\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e13\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMedium city\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSmall city\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eVillage\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e11\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFinancial situation (1\u0026ndash;6)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e4.17 (SD\u0026thinsp;=\u0026thinsp;1.24)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4.20 (SD\u0026thinsp;=\u0026thinsp;1.20)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e4.32(SD\u0026thinsp;=\u0026thinsp;1.0)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e\u003ch2\u003e2.3 Inclusion and exclusion criteria\u003c/h2\u003e\u003cp\u003eThe inclusion criteria were: (1) being over 18 years old, (2) fluency in the Polish language, (3) meeting the initial screening cut-off for mild depression on the CESD-20 (\u0026ge;\u0026thinsp;16 points), (4) having a diagnosed mild or moderate depressive episode as assessed by the M.I.N.I. structured online interview (Sheehan et al., \u003cspan citationid=\"CR62\" class=\"CitationRef\"\u003e1998\u003c/span\u003e), and (5) agreeing to the study protocol and randomization, including the possibility of being assigned to the waiting-list group. At screening both depression assessment tools were used to increase the validity of measure. In cases where only one cutoff score was exceeded, the final decision regarding inclusion was moved to the clinical interview. The exclusion criteria were: (1) severe depression or suicidality, (2) current participation in psychotherapy, (3) a diagnosis of substance use disorder, psychotic disorder, or bipolar disorder, as assessed in the M.I.N.I. structured online interview, and (4) recent modifications to or instability in psychiatric medication.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e\u003ch2\u003e2.4 Interventions\u003c/h2\u003e\u003cdiv id=\"Sec11\" class=\"Section3\"\u003e\u003ch2\u003e2.4.1 6-week synchronous iMBCT\u003c/h2\u003e\u003cp\u003eIn the iMBCTs format, participants were assigned to 4 groups of up to 15 individuals based on their indicated date preferences. Their profiles on the study platform were moved to the appropriate group, ensuring that each participant could access only the materials, announcements, and chat box specific to their group. Participants received email reminders about upcoming meetings and encouragement to engage in practice. If a participant remained inactive for five consecutive days, they received a gentle reminder containing psychoeducational content on topics such as perfectionism, the importance of habit formation, negative thought patterns, or difficult emotions. The meetings were conducted online via Google Meet or Zoom. Each session was led by an experienced mindfulness teacher with an MBCT certification, accompanied by an assistant responsible for technical support. In this study, the training was conducted by two male and two female teachers, each of whom was assigned to a single group for the entire six-week duration. The program was a shortened to 6-week adaptation (Holas et al., under review) of the standard MBCT protocol. The session titles were as follows:\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003e6-week iMBCT program\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eWeek\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eTopic of the meeting\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eContent\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eExercises/ Homework\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1.\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAwareness and automatic pilot\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eActing with(out) full awareness, raisin exercise, habitual patterns of distraction\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eMindful eating, Body scan\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2.\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eLiving in our heads\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eTendency to be caught up in thoughts about the past and future; relationship between thoughts and feelings, body sensations\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eSitting meditation, body scan. calendar of pleasant experiences\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e3.\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eBeing present in the body\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eRecognizing distracted mind; body as a gate to the mind and a breath as a stabilizer of attention\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eThree-minute breathing space, Hatha yoga, sitting meditation, calendar of unpleasant experiences\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e4.\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eRecognizing aversion\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eidentifying automatic reactions to discomfort, particularly the tendency to avoid or suppress difficult emotions.\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eThree-minute breathing space, Hatha yoga, sitting meditation,\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e5.\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAllowing and Letting be\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003epractice of acceptance; turning toward difficulty meditation\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eMeditation of difficulties, three-minute breathing space\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e6.\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eHow can I best take care of myself?\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eself-care and self-regulation strategies\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eBehavioral activation, three-minute breathing space, sitting meditation\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e After each meeting, participants received a summary of the session, a workbook, and guided meditation recordings for the upcoming week via the study platform. They could use the chat box to communicate with each other or seek guidance from the researcher or a psychologist with expertise in mindfulness, who responded to content-related inquiries.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec12\" class=\"Section3\"\u003e\u003ch2\u003e2.4.2 6-week asynchronous iMBCT\u003c/h2\u003e\u003cp\u003eIn the iMBCTa format, participants formed a single group of 58 individuals. On the dedicated study platform, all participants had access to a shared panel that included a chat box and study materials\u0026mdash;audio recordings and a workbook\u0026mdash;which were unlocked weekly in accordance with the session themes. The program was a pre-recorded equivalent of the synchronous version. Each week, participants received audio recordings introducing a new topic, guided meditation exercises (e.g., body scan, sitting meditation), reflective questions, psychoeducational content with emotional support, and instructions for the upcoming week. Similar to the synchronous condition, participants were reminded about the upcoming new sessions and encouraged to engage in daily practice. In cases of inactivity, automated reminder emails were sent, following the same procedure as in the synchronous format. To sustain the activity on the platform and provide support in situations of self-doubt, participants could use the chat box for communication with themselves and with a psychologist, who was answering few times a day.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec13\" class=\"Section3\"\u003e\u003ch2\u003e2.4.3 Control group\u003c/h2\u003e\u003cp\u003eAfter randomization, 53 participants were redirected to the \"waiting-list\" webpage on the platform, where they had access to a dedicated chat box exclusively for their group. Throughout the six-week waiting period, the group did not receive any form of intervention. During this time, three reminder emails were sent to inform participants about the study procedure and the mandatory second assessment required to gain access to the intervention. Upon completing all obligatory questionnaires, participants were granted access to the asynchronous iMBCT intervention.\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv id=\"Sec14\" class=\"Section2\"\u003e\u003ch2\u003e2.5 Symptom Measures\u003c/h2\u003e\u003cdiv id=\"Sec15\" class=\"Section3\"\u003e\u003ch2\u003e2.5.1 Primary outcomes\u003c/h2\u003e\u003cdiv id=\"Sec16\" class=\"Section4\"\u003e\u003ch2\u003e2.5.1.1 Depression\u003c/h2\u003e\u003cp\u003eTo enhance the validity of depression assessment prior to the interview, a second measure was utilized. The Center for Epidemiologic Studies Depression Scale (CES-D) is a widely used self-report tool designed to assess depressive symptoms in the general population (Radloff, \u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e1977\u003c/span\u003e). Participants respond to 20 items on a 4-point scale, with total scores ranging from 0 to 60, where higher scores indicate greater depressive symptomatology. The tool demonstrated strong psychometric properties, with Cronbach\u0026rsquo;s alpha coefficients of .89 at baseline, .92 post-intervention, and .90 at follow-up, indicating high internal consistency.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec17\" class=\"Section4\"\u003e\u003ch2\u003e2.5.1.2 Anxiety\u003c/h2\u003e\u003cp\u003eThe GAD-7 (Spitzer et al., 2006) is a 7-item questionnaire assessing the severity of Generalized Anxiety Disorder (GAD) symptoms, including nervousness, excessive worry, restlessness, and difficulty relaxing. Participants rate how often they experienced symptoms over the past 2 weeks on a 4-point scale (0\u0026thinsp;=\u0026thinsp;not at all, 3\u0026thinsp;=\u0026thinsp;nearly every day), with total scores ranging from 0 to 21. The GAD-7 demonstrates strong reliability and validity across various populations (Spitzer et al., 2006; Murray et al., 2010; Kroenke et al., 2007). Cronbach\u0026rsquo;s alpha for this scale was .87 in the pre-test, .88 in post-test and .87 in follow-up.\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv id=\"Sec18\" class=\"Section3\"\u003e\u003ch2\u003e2.5.2. Process measures\u003c/h2\u003e\u003cdiv id=\"Sec19\" class=\"Section4\"\u003e\u003ch2\u003e2.5.2.1 Mindfulness\u003c/h2\u003e\u003cp\u003eLevels of mindfulness were measured with the Five Facet Mindfulness Questionnaire (FFMQ) shortened from original 39 items (Baer et al., \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2008\u003c/span\u003e) to 24 items by Bohlmeijer and collaborators (2011). It is a self-report tool, designed to measure different aspects of mindfulness. It assesses five key components: observing, describing, acting with awareness, nonjudging of inner experience, and nonreactivity to inner experience. The FFMQ-24 has been used to assess mindfulness skills in relation to mental health, showing moderate \u0026ndash; strong associations with experiential avoidance, depression and anxiety (\u0026Aring;dn\u0026oslash;y et al., \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Cronbach\u0026rsquo;s alpha for this scale was .87 in the pretest, .92 in posttest and .94 in follow-up.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec20\" class=\"Section4\"\u003e\u003ch2\u003e2.5.2.2 Resilience\u003c/h2\u003e\u003cp\u003eResilience was measured with the SPP-25 (Skala Pomiaru Prężności \u0026ndash; Resilience Measurement Scale). It is a Polish, 25-item self-report questionnaire designed to assess psychological resilience, understood as an individual\u0026rsquo;s ability to adapt effectively to stress, adversity, and life challenges (Ogińska-Bulik \u0026amp; Juczyński, 2008). The scale conceptualizes resilience as a relatively stable personality trait that facilitates coping with both traumatic experiences and everyday stressors. Participants respond to each item using a 5-point Likert scale (0\u0026thinsp;=\u0026thinsp;strongly disagree to 4\u0026thinsp;=\u0026thinsp;strongly agree), with total scores ranging from 0 to 100, where higher scores indicate greater resilience. In our study the scale has demonstrated good internal consistency (Cronbach\u0026rsquo;s α\u0026thinsp;=\u0026thinsp;.92 in pretest, .93 in posttest and .91 in follow-up).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec21\" class=\"Section4\"\u003e\u003ch2\u003e2.5.2.3 Self- Compassion Scale Short-Form\u003c/h2\u003e\u003cp\u003eThe Self-Compassion Scale \u0026ndash; Short Form (SCS-SF) (Raes et al., 2011; Polish validation: Holas et al., 2023) was used to measure self-compassion. The SCS-SF consists of 12 items, rated on a five-point scale. The SCS-SF is strongly correlated with the long form of the scale (r\u0026thinsp;\u0026ge;\u0026thinsp;.97) and demonstrated consistently high internal reliability across populations (Neff \u0026amp; Pommier, 2013; Werner et al., 2012), with a reliability of Cronbach's α\u0026thinsp;=\u0026thinsp;.80 in the pretest, .87 in posttest and .75 in a follow-up measure in our study.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec22\" class=\"Section4\"\u003e\u003ch2\u003e2.5.2.4 Cognitive-fusion scale\u003c/h2\u003e\u003cp\u003eCognitive fusion was assessed using the Cognitive Fusion Questionnaire-7 (CFQ-7), a 7-item self-report measure designed to evaluate the extent to which individuals become entangled with their thoughts and experience difficulty distancing themselves from them (Gillanders et al., 2014). Participants rate items on a 7-point Likert scale (1\u0026thinsp;=\u0026thinsp;never true to 7\u0026thinsp;=\u0026thinsp;always true), with higher scores indicating greater cognitive fusion. The Polish validation confirmed its unidimensional structure and demonstrated strong psychometric properties (Baran et al., \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). In the present study, Cronbach\u0026rsquo;s α ranged from .91 to .94.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec23\" class=\"Section4\"\u003e\u003ch2\u003e2.5.2.5 Rumination\u003c/h2\u003e\u003cp\u003eIn the present study The Ruminative Responses Scale (RRS), a 22-item self-report questionnaire was used to assess rumination, a cognitive style characterized by a repetitive and passive focus on one's distress and its causes (Nolen-Hoeksema \u0026amp; Morrow, 1991). Participants respond to statements on a 4-point Likert scale (1\u0026thinsp;=\u0026thinsp;almost never to 4\u0026thinsp;=\u0026thinsp;almost always), with higher scores indicating greater rumination. The scale evaluates how individuals repetitively dwell on negative emotions and thoughts rather than engaging in active problem-solving. The RRS has demonstrated strong internal consistency, with Cronbach\u0026rsquo;s α- .90 in the pretest, .92 in posttest, .90 in a follow-up assessment.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec24\" class=\"Section4\"\u003e\u003ch2\u003e2.5.2.6 Experiential Avoidance\u003c/h2\u003e\u003cp\u003eExperiential avoidance was assessed using the Brief Experiential Avoidance Questionnaire (BEAQ), a 15-item self-report measure designed to evaluate the tendency to evade or suppress unpleasant internal experiences, such as distressing emotions, thoughts, or bodily sensations (G\u0026aacute;mez et al., 2014). The Polish validation study confirmed its bifactorial structure, identifying two dimensions: cognitive-emotional avoidance (CEA) and behavioral avoidance (BA) (Wardęszkiewicz \u0026amp; Holas, 2024). BEAQ items are rated on a 6-point Likert scale (1\u0026thinsp;=\u0026thinsp;strongly disagree to 6\u0026thinsp;=\u0026thinsp;strongly agree), with higher scores reflecting greater experiential avoidance. In the present study, Cronbach\u0026rsquo;s α ranged from .81 to .85, indicating good internal consistency.\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv id=\"Sec25\" class=\"Section3\"\u003e\u003ch2\u003e2.5.7 Negative effects\u003c/h2\u003e\u003cp\u003eNegative effects were assessed using the Negative Effects Questionnaire (NEQ; Rozental et al., 2014). Following the intervention, participants responded to 20 items (e.g., 'Difficult memories came back' or 'I felt anxious'), rating the intensity of specific symptoms on a scale from 0 ('not at all') to 4 ('extremely') and linking them to either intervention or external factors. The Cronbach\u0026rsquo;s α was .95 in the validation study (Rozental et al., \u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e2019\u003c/span\u003e).\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv id=\"Sec26\" class=\"Section2\"\u003e\u003ch2\u003e2.6 Data analysis\u003c/h2\u003e\u003cp\u003eIn order to assess the effectiveness of the intervention, an analysis using linear mixed models (LMM) was conducted. The analyses were based on a 3x3 design, including three groups (control, synchronous, and asynchronous) and three measurement points (although data for the control group were only available for two time points). The interaction between these two factors was included as fixed effects. Additionally, participant ID was included as a random effect to account for inter-individual variance.\u003c/p\u003e\u003cp\u003eThis model can be expressed using the following equation:\u003cdiv id=\"Equa\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equa\" name=\"EquationSource\"\u003e\n$$\\:{Y}_{ij}={\\beta\\:}_{0}+{\\beta\\:}_{1}\\cdot\\:{Group}_{i}+{\\beta\\:}_{2}\\cdot\\:{Measurement}_{j}+\\left({\\beta\\:}_{3}\\cdot\\:{Group}_{i}\\cdot\\:{Measurement}_{j}\\right)+{u}_{i}+{\\epsilon\\:}_{ij}$$\u003c/div\u003e\u003c/div\u003e;\u003c/p\u003e\u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{Y}_{ij}\\)\u003c/span\u003e\u003c/span\u003e \u0026ndash; outcome for participant \u003cem\u003ei\u003c/em\u003e at measurement \u003cem\u003ej\u003c/em\u003e\u003c/p\u003e\u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{\\beta\\:}_{0}\\)\u003c/span\u003e\u003c/span\u003e \u003cem\u003e\u0026ndash;\u003c/em\u003e intercept (constant)\u003c/p\u003e\u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{\\beta\\:}_{1},\\:{\\beta\\:}_{2},{\\beta\\:}_{3}\\)\u003c/span\u003e\u003c/span\u003e \u0026ndash; regression coefficients for fixed effects\u003c/p\u003e\u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{u}_{i}\\)\u003c/span\u003e\u003c/span\u003e \u0026ndash; random effect for participant \u003cem\u003ei\u003c/em\u003e\u003c/p\u003e\u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{\\epsilon\\:}_{ij}\\)\u003c/span\u003e\u003c/span\u003e \u0026ndash; random error\u003c/p\u003e\u003cp\u003eIn the present study the proportion of individuals who completed the third measurement accounted for less than half of the original sample. Based on the analyses by Chakraborty and Gu (2009), it was decided to use mixed models without imputation. Their research suggests that this approach is more efficient and leads to more reliable results, especially when dealing with a high percentage of missing data.\u003c/p\u003e\u003cp\u003eTo determine the mechanisms underlying the relationship between group membership and depression severity, a series of mediation analyses with parallel mediators was conducted using PROCESS macro by A. Hayes (Model 4). In each model, group membership served as the independent variable while depression severity at posttest as the dependent variable. Baseline scores of given variables were included as covariates to control for pre-existing differences. The significance of indirect effects was assessed using a bias-corrected bootstrapping procedure with 5000 resamples. Indirect effects were considered statistically significant if the 95% confidence interval did not include zero. Both the total indirect effect and the specific indirect effects of each mediator were analyzed. Partial mediation was inferred when the direct effect of group membership on depression severity remained significant after including the mediators in the model. To explore whether participants who dropped out of the study differed from those who completed it, a series of independent-samples t-tests were conducted on baseline demographic and psychological variables. These analyses aimed to identify potential predictors of attrition by comparing completers and non-completers across key characteristics measured prior to the intervention. In addition to the full-sample comparison, analyses were also conducted separately within the synchronous and asynchronous conditions to examine whether dropout patterns varied by intervention format.\u003c/p\u003e\u003c/div\u003e"},{"header":"3. Results","content":"\u003cdiv id=\"Sec28\" class=\"Section2\"\u003e\u003ch2\u003e2.1 Effects\u003c/h2\u003e\u003cdiv id=\"Sec29\" class=\"Section3\"\u003e\u003ch2\u003e2.1.1 Depression (CES-D)\u003c/h2\u003e\u003cp\u003eThe model was evaluated using BIC\u0026thinsp;=\u0026thinsp;2432.98. Fixed effects explained 31.4% of CESD variance (marginal R\u0026sup2; = .314), while both fixed and random effects accounted for 53.7% (conditional R\u0026sup2; = .537). ICC\u0026thinsp;=\u0026thinsp;.223 indicated that 22.3% of variance was due to random effects. A significant group effect was found (\u003cem\u003eF\u003c/em\u003e(2, 175.31)\u0026thinsp;=\u0026thinsp;7.53, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001), with higher depression levels in the control group than in the asynchronous (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001) and synchronous (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.008) groups. No significant difference was observed between the intervention groups (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.068). A significant time effect (\u003cem\u003eF\u003c/em\u003e(2, 205.10)\u0026thinsp;=\u0026thinsp;76.97, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001) showed a decline in CESD scores from the first to later measurements (both \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001), with no significant difference between the posttest and follow-up assessments (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.129). A significant interaction (\u003cem\u003eF\u003c/em\u003e(3, 202.43)\u0026thinsp;=\u0026thinsp;13.50, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001) indicated that depression severity remained stable in the control group (\u003cem\u003eF\u003c/em\u003e(1, 176.47)\u0026thinsp;=\u0026thinsp;2.98, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.086), whereas both intervention groups showed significant reductions in the posttest and follow-up (asynchronous: \u003cem\u003eF\u003c/em\u003e(2, 210.64)\u0026thinsp;=\u0026thinsp;57.44, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001; synchronous: \u003cem\u003eF\u003c/em\u003e(2, 206.81)\u0026thinsp;=\u0026thinsp;33.70, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001). No significant group differences were found at baseline (\u003cem\u003eF\u003c/em\u003e(2, 297.49)\u0026thinsp;=\u0026thinsp;0.61, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.546), confirming similar initial depression levels. However, differences emerged in posttest (\u003cem\u003eF\u003c/em\u003e(2, 320.73)\u0026thinsp;=\u0026thinsp;19.14, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001) and follow-up (\u003cem\u003eF\u003c/em\u003e(1, 331.53)\u0026thinsp;=\u0026thinsp;4.31, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.039). Post hoc analyses showed that at posttest, the control group had significantly higher depression scores than both the asynchronous (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001) and synchronous (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001) groups, with no difference between the intervention groups (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.096). At follow-up, depression was higher in the synchronous than in the asynchronous group (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.039). Estimated marginal means are provided in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e5\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003e\u003cem\u003eEstimated marginal means for CESD by measurement time and group membership\u003c/em\u003e\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"6\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eMeasurement\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eGroup\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e\u003cem\u003eM\u003c/em\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e\u003cem\u003eSE\u003c/em\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e\u003cp\u003e95% CI\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u003cem\u003eLL\u003c/em\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003e\u003cem\u003eUL\u003c/em\u003e\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eWLC\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e26.55\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.21\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e24.17\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e28.92\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003easynchronous\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e27.86\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.14\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e25.62\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e30.11\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003esynchronous\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e28.33\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e26.06\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e30.60\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eWLC\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e24.12\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.22\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e21.72\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e26.51\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003easynchronous\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e12.69\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.47\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e9.80\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e15.58\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003esynchronous\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e16.94\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.32\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e14.35\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e19.54\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eWLC\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003easynchronous\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e12.60\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.72\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e9.22\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e15.99\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003esynchronous\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e17.80\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.82\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e14.22\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e21.39\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eThe parameters for fixed effects are presented in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e6\u003c/span\u003e. The analysis showed that depression severity was significantly higher in the control group and significantly lower in the asynchronous group compared to the reference group (synchronous). CESD scores were higher at the first measurement compared to the reference measurement (third measurement)\u0026mdash;these parameters confirm the post hoc pairwise comparisons.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 6\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003e\u003cem\u003eRegression parameters for fixed effects in the model explaining CESD.\u003c/em\u003e\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"7\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eParameters\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e\u003cem\u003eb\u003c/em\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e\u003cem\u003eSE\u003c/em\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e\u003cem\u003et\u003c/em\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e\u003cp\u003e95% \u003cem\u003eCI\u003c/em\u003e\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003e\u003cem\u003eLL\u003c/em\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003e\u003cem\u003eUL\u003c/em\u003e\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eIntercept\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e17.80\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e1.82\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e328.16\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e14.22\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e21.39\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePretest\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e10.52\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e1.95\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e222.05\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e6.69\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e14.36\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePosttest\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e-0.86\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e2.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e205.12\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.667\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e-4.80\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e3.08\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eWLC\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e7.17\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e1.80\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e312.94\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e3.64\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e10.70\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAsynchronous\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e-5.20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e2.51\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e331.53\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.039\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e-10.13\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e-0.27\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePretest * WLC\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e-8.95\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e2.05\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e187.69\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e-12.99\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e-4.91\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePretest * asynchronous\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e4.74\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e2.68\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e224.09\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.079\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e-0.55\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e10.03\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePosttest * asynchronous\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e0.95\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e2.80\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e197.69\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.736\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e-4.58\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e6.47\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec30\" class=\"Section3\"\u003e\u003ch2\u003e2.1.3 Anxiety\u003c/h2\u003e\u003cp\u003eThe model was evaluated using BIC\u0026thinsp;=\u0026thinsp;1947.73. Fixed effects explained 30.5% of variance (R\u0026sup2; = .305), while total variance explained was 56.1% (R\u0026sup2; = .561). ICC\u0026thinsp;=\u0026thinsp;0.256 indicated that 25.6% of variance was due to random effects. A significant group effect (\u003cem\u003eF\u003c/em\u003e(2, 167.25)\u0026thinsp;=\u0026thinsp;76.39, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.002) showed that anxiety was higher in the control group than in asynchronous (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001) and synchronous (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.001) groups, with no difference between intervention groups (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.528). A significant time effect (\u003cem\u003eF\u003c/em\u003e(2, 192.82)\u0026thinsp;=\u0026thinsp;80.16, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001) revealed a decline in anxiety from the first to later measurements (both \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001), with no significant difference between the second and third time points (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.093). A significant interaction (\u003cem\u003eF\u003c/em\u003e(3, 190.69)\u0026thinsp;=\u0026thinsp;11.47, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001) indicated that anxiety remained stable in the control group, while both intervention groups showed significant reductions in later assessments (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001). No significant group differences were found at baseline (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.346) or at the final assessment (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.372), but the control group had higher anxiety than both intervention groups at the second time point (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001). No difference was observed between the synchronous and asynchronous groups (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;1.000).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec31\" class=\"Section3\"\u003e\u003ch2\u003e2.1.4 Cognitive Fusion\u003c/h2\u003e\u003cp\u003eThe model was assessed using BIC\u0026thinsp;=\u0026thinsp;2237.79. Fixed effects accounted for 24.0% of variance (R\u0026sup2; = .240), while the total explained variance reached 62.8% (R\u0026sup2; = .628). ICC\u0026thinsp;=\u0026thinsp;0.387 indicated that 38.7% of variance was attributed to random effects. A significant group effect (\u003cem\u003eF\u003c/em\u003e(2, 183.82)\u0026thinsp;=\u0026thinsp;5.64, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.004) showed that cognitive fusion was highest in the control group, significantly exceeding levels in both asynchronous (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001) and synchronous (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001) groups. No differences were found between the two intervention groups (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;1.000). A main effect of time was also significant (\u003cem\u003eF\u003c/em\u003e(2, 203.72)\u0026thinsp;=\u0026thinsp;55.25, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001), indicating a progressive decline in cognitive fusion over repeated measurements (all \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001). A significant interaction (\u003cem\u003eF\u003c/em\u003e(3, 202.61)\u0026thinsp;=\u0026thinsp;14.46, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001) revealed that cognitive fusion remained stable in the control group, while both intervention groups experienced a significant reduction between the first and later assessments. No group differences emerged at baseline (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.705) or the final measurement (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.516), but fusion levels in the control group were significantly higher at the second time point compared to the intervention groups (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). No difference was detected between synchronous and asynchronous conditions (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;1.000).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec32\" class=\"Section3\"\u003e\u003ch2\u003e2.1.5 Resilience\u003c/h2\u003e\u003cp\u003eThe model was evaluated using BIC\u0026thinsp;=\u0026thinsp;2623.38. Fixed effects explained 12.7% of variance (R\u0026sup2; = .127), while total variance explained was 74.9% (R\u0026sup2; = .749). ICC\u0026thinsp;=\u0026thinsp;.622 indicated that 62.2% of variance was attributable to random effects. A significant group effect (\u003cem\u003eF\u003c/em\u003e(2, 173.89)\u0026thinsp;=\u0026thinsp;4.05, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.019) showed that psychological resilience was lower in the control group compared to both asynchronous (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.004) and synchronous (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.003) groups, with no significant difference between intervention groups (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;1.000). A significant time effect (\u003cem\u003eF\u003c/em\u003e(2, 176.77)\u0026thinsp;=\u0026thinsp;41.55, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001) indicated a progressive increase in resilience across measurements (all \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001). A significant interaction (\u003cem\u003eF\u003c/em\u003e(3, 176.44)\u0026thinsp;=\u0026thinsp;5.80, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001) revealed that resilience remained stable in the control group, whereas both intervention groups showed a significant increase from the first to later measurements, with no difference between the second and third time points. No group differences were observed at baseline (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.558) or in the final measurement (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.855), but the control group had lower resilience levels at the second time point compared to both intervention groups (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001). No difference was found between synchronous and asynchronous groups (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;1.000).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec33\" class=\"Section3\"\u003e\u003ch2\u003e2.1.6 Experiential Avoidance\u003c/h2\u003e\u003cp\u003eFor BA, the model (BIC\u0026thinsp;=\u0026thinsp;1963.25) explained 3.0% of variance through fixed effects (R\u0026sup2; = .030), while total variance explained was 58.9% (R\u0026sup2; = .589). ICC\u0026thinsp;=\u0026thinsp;.559 indicated that 55.9% of variance was due to individual differences. The group effect was not significant (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.236), with comparable BA levels across groups. A small but significant time effect (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.029) showed a decrease in BA from the first to the third measurement, while the interaction was non-significant (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.548). Regression analysis confirmed that the only significant effect was the reduction in BA over time. For CEA, a separate model (BIC\u0026thinsp;=\u0026thinsp;2133.07) explained 20.4% of variance through fixed effects (R\u0026sup2; = .204), with total variance explained at 65.4% (R\u0026sup2; = 0.654). ICC\u0026thinsp;=\u0026thinsp;.449 suggested that 44.9% of variance was due to individual differences. A significant group effect (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001) indicated that CEA was higher in the control group than in both intervention groups (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001), with no difference between the asynchronous and synchronous groups (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.285). A significant time effect (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001) demonstrated a progressive decline in CEA across all measurements. A significant interaction effect (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001) showed that CEA remained stable in the control group between the first and second measurements (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.209), while both intervention groups experienced a significant reduction from the first to later time points (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001), with no further change between the second and third measurements. No significant differences were found at baseline (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.293) or the final measurement (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.267). However, at the second measurement, CEA was significantly higher in the control group compared to both intervention groups (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001), with no difference between the synchronous and asynchronous groups (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.471).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec34\" class=\"Section3\"\u003e\u003ch2\u003e2.1.7 Mindfulness\u003c/h2\u003e\u003cp\u003eThe model was evaluated using BIC\u0026thinsp;=\u0026thinsp;2587.46. Fixed effects accounted for 28.0% of the variance (R\u0026sup2; = .280), while the total explained variance was 68.8% (R\u0026sup2; = .688). The intraclass correlation coefficient (ICC\u0026thinsp;=\u0026thinsp;.408) indicated that 40.8% of the variance was attributable to individual differences. A significant group effect (\u003cem\u003eF\u003c/em\u003e(2, 186.21)\u0026thinsp;=\u0026thinsp;6.95, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.001) showed that mindfulness levels were lower in the control group compared to the asynchronous (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001) and synchronous (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001) groups, with no significant difference between the two intervention groups (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;1.000). A significant time effect (\u003cem\u003eF\u003c/em\u003e(2, 199.10)\u0026thinsp;=\u0026thinsp;81.84, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001) indicated a steady increase in mindfulness over time (all \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001), with mean FFMQ scores rising from 69.87 at baseline to 80.04 at the second measurement and 87.69 at the third measurement. A significant interaction effect (F(3, 198.18)\u0026thinsp;=\u0026thinsp;16.95, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001) revealed that mindfulness remained stable in the control group between the first and second assessments (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.456), whereas both intervention groups showed a significant increase from the first to subsequent measurements (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001), with no further improvement between the second and third time points. No significant differences were found between groups at baseline (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.406) or at the final assessment (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.311). However, at the second measurement, mindfulness levels in the control group were significantly lower than in both intervention groups (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001). No differences were detected between the synchronous and asynchronous groups (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.750).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec35\" class=\"Section3\"\u003e\u003ch2\u003e2.1.8 Rumination\u003c/h2\u003e\u003cp\u003eThe model was evaluated using BIC\u0026thinsp;=\u0026thinsp;2496.07. Fixed effects explained 17.4% of variance (R\u0026sup2; = 0.174), while total variance explained was 56.0% (R\u0026sup2; = 0.560). ICC\u0026thinsp;=\u0026thinsp;0.386 indicated that 38.6% of variance was attributable to individual differences. The group effect was not significant (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.099), but post hoc comparisons revealed that rumination was higher in the control group than in the asynchronous group (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.005), while the synchronous group did not differ significantly from either. A significant time effect (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001) indicated a progressive decline in rumination across assessments (all \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001), with no significant difference between the second and third measurements (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.088). A significant interaction effect (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001) showed that rumination levels remained stable in the control group between the first and second assessments (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.222), whereas both intervention groups exhibited a significant decrease between the first and later time points (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001), with no further decline between the second and third measurements. No differences were found at baseline (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.440), but at the second measurement, rumination was significantly higher in the control group compared to the asynchronous group (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.002). By the third measurement, the synchronous group had significantly higher rumination than the asynchronous group (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.019).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec36\" class=\"Section3\"\u003e\u003ch2\u003e2.1.9 Self-compassion\u003c/h2\u003e\u003cp\u003eThe model was evaluated using BIC\u0026thinsp;=\u0026thinsp;2239.97. Fixed effects explained 16.8% of variance (R\u0026sup2; = .168), while total variance explained was 45.5% (R\u0026sup2; = .455). ICC\u0026thinsp;=\u0026thinsp;.287 indicated that 28.7% of variance was due to individual differences. The group effect was not significant (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.066), but post hoc analysis showed that self-compassion was lower in the control group compared to both the asynchronous (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.030) and synchronous groups (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.007), with no difference between the intervention groups (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.000). A significant time effect (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001) indicated a gradual increase in self-compassion across assessments, with no difference between the second and third measurements (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.227). A significant interaction effect (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001) showed that self-compassion remained stable in the control group between the first and second assessments (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.490), while both intervention groups exhibited a significant increase from the first to later measurements (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001), with no further difference between the second and third time points. No differences were found at baseline (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.139) or at the final measurement (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.120). However, at the second measurement, self-compassion was significantly lower in the control group compared to the asynchronous (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001) and synchronous groups (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.003), with no significant difference between the intervention groups (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.291).\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv id=\"Sec37\" class=\"Section2\"\u003e\u003ch2\u003e2.2 Mechanisms of change\u003c/h2\u003e\u003cp\u003eOut of 21 examined models (Appendix), the best characteristic had mindfulness and cognitive fusion (measured at the second time point) as mediators of the relationship between group membership and depression severity (CESD score at the second time point). FFMQ, CFQ, and CESD from the first measurement were included as control variables. The analysis revealed a significant relationship between group membership and mindfulness (β\u0026thinsp;=\u0026thinsp;.93, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001), as well as between group membership and cognitive fusion (β = \u0026minus;\u0026thinsp;.95, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001). Participants in the interventions group reported higher mindfulness and lower cognitive fusion than those in the control group. Mindfulness was negatively associated with depression severity when controlling for group membership and baseline values (β = \u0026minus;\u0026thinsp;.30, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.001), indicating that higher mindfulness levels corresponded with lower depression severity. Conversely, cognitive fusion was positively associated with depression severity (β\u0026thinsp;=\u0026thinsp;.35, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001), meaning higher fusion levels were linked to increased depression symptoms. After accounting for mediators, the direct effect of group membership on depression remained significant and negative (β = -0.30, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.049). Mediation analysis confirmed a significant total indirect effect (b = -6.52; 95% CI [-9.25, -4.32]), with both mindfulness (b = -2.98; 95% CI [-5.46, -0.82]) and cognitive fusion (b = -3.54; 95% CI [-6.05, -1.65]) acting as significant mediators. The findings support partial mediation, as the direct effect between group membership and depression remained significant after accounting for mediators. This highlights the crucial role of mindfulness and cognitive fusion in explaining the relationship between group membership and depression severity.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 7\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003e\u003cem\u003eSummary of mediation model for the relationship between group membership and depression severity (CESD)\u003c/em\u003e\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"10\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e\u003cp\u003e\u003cem\u003eCI\u003c/em\u003e 95%\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eModel\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eEffect\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u003cem\u003eB\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cem\u003eSE\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u003cem\u003eβ\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e\u003cem\u003et\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e\u003cem\u003eLL\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e\u003cem\u003eUL\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e\u003cem\u003eR\u003c/em\u003e\u003csup\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"8\" rowspan=\"9\"\u003e\u003cp\u003e\u003cb\u003eModel 1\u003c/b\u003e\u003c/p\u003e\u003cp\u003eM1: FFMQ\u003c/p\u003e\u003cp\u003eM2: CFQ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003ea1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e13.21\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.86\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.93\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e7,10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0,001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e9.53\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e16.90\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003ea2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-7.86\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e-0.95\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e-6,84\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0,001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e-10.14\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e-5.59\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eb1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-0.23\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.06\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e-0.30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e-3,50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e0,001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e-0.35\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e-0.10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eb2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.45\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.11\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.35\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e4,05\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0,001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e0.23\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e0.67\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003ec\u0026rsquo;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-3.16\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.59\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e-0.30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e-1,98\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e0,049\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e-6.31\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e-0.01\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e0.52\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003ec\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-9.68\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.63\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e-12.89\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e-6.45\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003ec \u0026ndash; c\u0026rsquo;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-6.52\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.24\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e-0.62\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e-9.25\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e-4.32\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eFFMQ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-2.98\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.18\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e-0.28\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e-5.46\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e-0.82\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCFQ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-3.54\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.12\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e-0.34\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e-6.05\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e-1.65\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"10\"\u003e\u003cem\u003eNote\u003c/em\u003e. In each model, the independent variable is group membership, while the dependent variable is depression severity (CESD score). \u003csup\u003ea\u003c/sup\u003e c \u0026ndash; c\u0026rsquo; represents the total indirect effect, testing the mediation effect with both mediators included. If the confidence intervals do not contain zero, the mediation effect is statistically significant at p\u0026thinsp;\u0026lt;\u0026thinsp;0.05. CFQ \u0026ndash; Cognitive Fusion; FFMQ \u0026ndash; Mindfulness\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec38\" class=\"Section2\"\u003e\u003ch2\u003e2.3 Negative effects\u003c/h2\u003e\u003cp\u003eAfter the intervention, 76 participants completed the Negative Effects Questionnaire (NEQ). To assess the overall intensity of negative effects, a mean NEQ score was calculated for each participant. The average NEQ score was 0.28 (SD\u0026thinsp;=\u0026thinsp;.36), with a minimum of 0.00, a maximum of 1.65, and a mode of 0.18. The mean number of summed negative effect items per participant was 5.58 (SD\u0026thinsp;=\u0026thinsp;7.12), ranging from 0 to 33. Fourteen participants (17%) reported no negative effects, while the remaining 83% reported experiencing at least one negative effect during the intervention. For 75% of participants, the impact of negative effects ranged from experiencing multiple symptoms with minimal impact (up to 7 symptoms) to experiencing fewer symptoms (around 2) with strong or extreme impact. The most frequently reported negative effects were: increased levels of stress (n\u0026thinsp;=\u0026thinsp;24, mean impact\u0026thinsp;=\u0026thinsp;1.7), greater worry (n\u0026thinsp;=\u0026thinsp;20, mean impact\u0026thinsp;=\u0026thinsp;1.3), more frequent unpleasant feelings (n\u0026thinsp;=\u0026thinsp;20, mean impact\u0026thinsp;=\u0026thinsp;1.8), recurring unpleasant memories (n\u0026thinsp;=\u0026thinsp;24, mean impact\u0026thinsp;=\u0026thinsp;1.54).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec39\" class=\"Section2\"\u003e\u003ch2\u003e2.4 Treatment response\u003c/h2\u003e\u003cp\u003eIn a study on clinical significance and depression assessment tools, Kounali et al. (\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2022\u003c/span\u003e) found that a 20% reduction in the total questionnaire score can be classified as a minimal clinically important difference (MCID). Therefore, in the present study, a 20% reduction was used as the cutoff for \"improvement.\" Scores between 0% and 20% were categorized as \"no change,\" while an increased severity of symptoms was classified as \"deterioration.\" Among the 77 participants who completed the post-test CES-D measurement, 62 (81%) met the criteria for a clinically significant treatment response, scoring more than 20% lower on the depression scale compared to their pre-intervention scores. The mean improvement was 44%, with a median of 51%. Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e8\u003c/span\u003e presents detailed data, stratified by the asynchronous and synchronous groups.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 8\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"8\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eDeterioration\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNo change\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eImprovement\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eMean improvement\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eMedian\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003eMin\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\"\u003e\u003cp\u003eMax\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAsynchronous\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e3 (9%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e2 (6%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e29 (85%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e51%(SD\u0026thinsp;=\u0026thinsp;35)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e55%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e-57%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e98%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSynchronous\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e4 (9%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e6 (14%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e33 (77%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e39%(SD\u0026thinsp;=\u0026thinsp;32)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e45%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e-52%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e92%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec40\" class=\"Section2\"\u003e\u003ch2\u003e2.5 Engagement\u003c/h2\u003e\u003cp\u003e Participants' activity on the platform was tracked based on login counts and time spent on audio recordings. However, data from the synchronous group were excluded from analysis, as mindfulness instructors allowed to use for guided meditation recordings their own websites, YouTube channels, or MP3 files they provided \u0026ndash; what could not be controlled. In the asynchronous group, the mean time spent on recordings was 611 minutes (SD\u0026thinsp;=\u0026thinsp;411), with a minimum of 33 minutes and a maximum of 1,715 minutes (approximately 28 hours). The mean number of logins was 100 (SD\u0026thinsp;=\u0026thinsp;83; min: 15, max: 457) in the asynchronous and 101 (SD\u0026thinsp;=\u0026thinsp;92; min\u0026thinsp;=\u0026thinsp;91 and max\u0026thinsp;=\u0026thinsp;405) in synchronous group.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab6\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 9\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003e\u003cem\u003eEngagement metrics: session count and time spent by synchronous vs. asynchronous groups\u003c/em\u003e\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"7\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMean time\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eMin time\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eMax time\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eMean session number\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eMin\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003eMax\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAsynchronous\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e611\u003c/p\u003e\u003cp\u003e(SD\u0026thinsp;=\u0026thinsp;411)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e33\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1715\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e100(SD\u0026thinsp;=\u0026thinsp;83)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e457\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSynchronous\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e327\u003c/p\u003e\u003cp\u003e(SD\u0026thinsp;=\u0026thinsp;543)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e2771\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e101(SD\u0026thinsp;=\u0026thinsp;92)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e11\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e405\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"7\" nameend=\"c7\" namest=\"c1\"\u003e\u003cp\u003eNote. Time refers to the duration spent on recordings, not total time on the platform.\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec41\" class=\"Section2\"\u003e\u003ch2\u003e2.6 Attrition\u003c/h2\u003e\u003cp\u003eOut of 170 participants randomized into three conditions, 125 (74%) completed the posttest assessment. Attrition rates varied across groups: 28% in the synchronous group, 45% in the asynchronous group, and 4% in the control group. Participants who remained inactive for more than five days received automated emails containing psychoeducational content and encouragement to re-engage with the program. However, those who did not respond to these emails or remained inactive for over three weeks were classified as dropouts. Upon logging into the platform, they were presented with a pop-up requesting feedback on their reasons for discontinuation. After the three months, in the follow-up, the attrition was 59% in the asynchronous and 66% in synchronous condition. As a total of 45 participants did not complete the posttest, the amount of collected feedback was limited. The reported reasons for dropout included: Perceiving the program as too intense or experiencing frustration due to an inability to complete all tasks (n\u0026thinsp;=\u0026thinsp;4), finding another solution that better suited their needs (n\u0026thinsp;=\u0026thinsp;1), deciding to seek psychiatric consultation instead (n\u0026thinsp;=\u0026thinsp;1)\u003c/p\u003e\u003cp\u003eNo statistically significant differences were found between completers and non-completers on any of the baseline variables, either in the full sample or within the separate intervention conditions (all ps\u0026thinsp;\u0026gt;\u0026thinsp;.05). This included demographic factors (e.g., gender, education) as well as psychological variables such as baseline levels of depression, anxiety, mindfulness. Although a few comparisons approached significance (e.g., rumination and gender in the synchronous group), all effect sizes were small to moderate and non-significant. These findings suggest that dropout was not associated with specific participant characteristics.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec42\" class=\"Section2\"\u003e\u003ch2\u003e2.7 The perception of the program\u003c/h2\u003e\u003cp\u003eAt the end of the posttest, participants were asked to rate the extent to which the program met their expectations on a scale from 0 to 4, with an option to provide additional comments. Of the 62 respondents (81% response rate), the average rating was 3.16 (SD\u0026thinsp;=\u0026thinsp;.61). The highest rating, 4 (\"definitively yes\"), was selected by 17 participants, while the lowest, 2 (\"hard to say\"), was chosen by 7 participants. Among those least satisfied, elaborated responses highlighted concerns such as the large number of exercises and the irritating need for sustained focus during exercises (n\u0026thinsp;=\u0026thinsp;2), frustration with the difficulty of establishing a habit and maintaining regular practice (n\u0026thinsp;=\u0026thinsp;2), and challenges in translating mindfulness knowledge and skills into self-efficacy (n\u0026thinsp;=\u0026thinsp;1). Conversely, among participants whose expectations were met, the most common themes in their comments included noticeable improvements in mood and stress reduction (n\u0026thinsp;=\u0026thinsp;12), increased self-awareness and new insights (n\u0026thinsp;=\u0026thinsp;6), and perceived benefits of the program (n\u0026thinsp;=\u0026thinsp;6). Additional comments (n\u0026thinsp;=\u0026thinsp;9) covered recommendations for the researchers and reflections on the challenges of mindfulness practice.\u003c/p\u003e\u003c/div\u003e"},{"header":"4. Discussion","content":"\u003cp\u003eThe aim of the study was to evaluate the effectiveness of an online Mindfulness-Based Cognitive Therapy intervention in individuals experiencing depression, and to compare two delivery formats - online group synchronous MBCT and guided asynchronous iMBCT. Furthermore to identify key mechanisms of change. Results indicated that both intervention formats led to significant improvements across all measured outcomes, including depressive symptoms, resilience, self-compassion, rumination, cognitive fusion, experiential avoidance, and mindfulness. Notably, there were no significant differences between the synchronous and asynchronous conditions at posttest or follow-up, suggesting that both delivery formats may be comparably effective in reducing psychopathological symptoms and enhancing self-regulation.\u003c/p\u003e\u003cp\u003eThese findings are consistent with prior studies demonstrating the effectiveness of iMBCT in reducing symptoms of anxiety and depression (Holas \u0026amp; Wardęszkiewicz, under review; Liu et al., \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2024\u003c/span\u003e; Rodrigues et al., \u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e2024\u003c/span\u003e; Nissen et al., \u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Segal et al., \u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e2020\u003c/span\u003e, Boettcher et al., \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2014\u003c/span\u003e), and in promoting resilience (Holas \u0026amp; Wardęszkiewicz, 2025. Moreover, the results align with the theoretical framework of MBCT, which posits that cultivating mindfulness - defined as nonjudgmental awareness of the present-moment (Kabat-Zinn, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2015\u003c/span\u003e) - interrupts maladaptive cognitive and emotional patterns such as rumination and cognitive fusion (Foroughi et al., 2020). By fostering the ability to observe thoughts and feelings as passing mental events, rather than identifying with them (Teasdale et al., \u003cspan citationid=\"CR73\" class=\"CitationRef\"\u003e2002\u003c/span\u003e), mindfulness is theorized to reduce the risk of depressive relapse (Segal et al., \u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e2012\u003c/span\u003e). Supporting this model, the present study identified mindfulness and cognitive fusion as the most robust mediators of treatment response. Similar findings were reported by Dimidjian and collaborators (2023), who observed that improvements following online MBCT were mediated by decentering, mindfulness, and reductions in rumination. Notably, improvement in cognitive defusion was observed despite the absence of the specific session typically dedicated to this concept in standard MBCT (\u0026ldquo;Thoughts are not facts\u0026rdquo;). This finding suggests that the capacity to relate to thoughts in a decentered way may develop more broadly throughout the MBCT training, even in its abbreviated format.\u003c/p\u003e\u003cp\u003eDespite the comparable efficacy across conditions, notable differences in attrition emerged between the two online abbreviated MBCT formats. Specifically, 45% of participants in the asynchronous condition discontinued the intervention prior to the posttest, compared to 28% in the synchronous group. These figures are within the range observed in previous online MBIs, where dropout rates have varied from 8\u0026ndash;65% (Spijkerman et al., 2021) and from 2.5\u0026ndash;57%, with a mean of 25.8% (SD\u0026thinsp;=\u0026thinsp;17.1) in another meta-analysis (Reangsing et al., \u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e2023\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eWhile no prior study has directly compared synchronous and asynchronous mindfulness-based interventions for depression, findings from broader online intervention literature consistently show that synchronous formats - characterized by real-time interaction and therapist guidance - are associated with greater adherence (Mammarella et al., \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2024\u003c/span\u003e; Andersson \u0026amp; Titov, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). In contrast, asynchronous formats often show higher attrition, likely due to limited support and a lack of immediate feedback (Wolever et al., \u003cspan citationid=\"CR81\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). Nonetheless, asynchronous delivery offers important advantages, including time flexibility, scalability, and lower operational demands (Andersson \u0026amp; Titov, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). Given the comparable symptom reduction observed in both formats, the question may no longer be which format is superior in effectiveness, but rather how to optimize user engagement and minimize dropout, particularly in less guided interventions. Future studies should focus on developing and testing strategies to enhance adherence in asynchronous interventions, such as reminders, chatbot-guidance, or hybrid formats.\u003c/p\u003e\u003cp\u003eThe findings suggest that structured, evidence-based programs like iMBCT - whether delivered synchronously or asynchronously - may serve as accessible, low-threshold interventions for the depressed population. In real-world healthcare, such interventions could be recommended following psychiatric consultations in less severe cases or offered as a meaningful form of support during waiting periods for in-person psychotherapy. Promoting early access to online interventions targeting self-regulation and mindfulness could help prevent symptom escalation and reduce long-term treatment needs.\u003c/p\u003e\u003cdiv id=\"Sec44\" class=\"Section2\"\u003e\u003ch2\u003e3.1 Limitations\u003c/h2\u003e\u003cp\u003eOne limitation of this study is that not all components of the intervention were delivered within a single, integrated study platform. While participants in the asynchronous condition completed the entire program within the platform, those in the synchronous condition attended live sessions via external tools such as Zoom or Google Meet. Additionally, mindfulness instructors provided external resources for guided meditation practice (e.g., personal websites or YouTube links). Under these circumstances, it was not possible to comprehensively track participant engagement in the synchronous condition. A second limitation concerns the use of a waiting-list control group rather than an active comparator. Although a waitlist design controls for some nonspecific factors, such as the passage of time, it may overestimate treatment effects and does not reflect real-life behavior, where individuals often search for alternative forms of support while waiting (Freedland et al., \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2011\u003c/span\u003e; Cunningham et al., \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2013\u003c/span\u003e). Moreover, the absence of a follow-up assessment in the control group limits the ability to compare long-term outcomes across all conditions. However, requiring participants with depression to remain without access to intervention for over four months was considered ethically inappropriate. Future studies should consider including an active control, such as treatment-as-usual (TAU) with a follow-up assessment. Another limitation involves the demographic homogeneity of the sample, which was predominantly female and well-educated. This overrepresentation is typical in mindfulness-based intervention research, where women often account for more than 70% of participants (Eichel et al., \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). However, it restricts the generalizability of the findings. Future research should prioritize the inclusion of more diverse populations to better understand the applicability and impact of iMBCT across sociodemographic groups.\u003c/p\u003e\u003cp\u003eAll outcomes in this study were assessed via self-report questionnaires. While the MINI was used for diagnostic screening during recruitment, the absence of clinician-rated or behavioral outcome measures may introduce biases. Incorporating objective assessments in future trials would enhance the validity of the findings.\u003c/p\u003e\u003cp\u003eFinally, the intervention was a shortened adaptation of the standard 8-week MBCT protocol, delivered over six weeks. Although the content remained consistent with MBCT\u0026rsquo;s core structure, the shortened duration may have limited the opportunity for skill consolidation or depth of practice. Future research should explore the comparative effectiveness of full-length and brief MBCT formats to better understand how modifications impact outcomes and adherence.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec45\" class=\"Section2\"\u003e\u003ch2\u003e3.2 Future directions\u003c/h2\u003e\u003cp\u003eBuilding on the present findings, future research could explore the effectiveness of various engagement strategies - such as incorporating chatbots or blending design with other forms of real-time feedback - to improve adherence in asynchronous formats. Efforts to recruit more diverse samples, particularly with regard to gender, education level, and digital literacy, would also help address current limitations in generalizability. Additionally, studying the impact of intervention length may offer valuable insights, as online MBIs vary widely in duration, typically ranging from 2 to 12 weeks (Spijkerman et al., \u003cspan citationid=\"CR68\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). Understanding how program length influences both adherence and perceived effectiveness could help optimize delivery for different populations. Future research could also explore individual characteristics that predict greater benefit from one delivery format over another, including factors such as self-discipline, motivation, attitudes towards psychological online interventions or confidence in therapy effectiveness.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec46\" class=\"Section2\"\u003e\u003ch2\u003e3.3 Conclusion\u003c/h2\u003e\u003cp\u003eThe present study demonstrated that both synchronous group and asynchronous formats of iMBCT may serve as effective interventions for individuals experiencing mild to moderate depressive symptoms. While the synchronous format was associated with higher completion rates, the asynchronous format offers greater time flexibility and showed comparable effects in reducing depression and anxiety, as well as enhancing resilience, self-compassion, mindfulness, and cognitive defusion. These findings support the scalability of iMBCT and highlight the importance of offering diverse delivery formats to accommodate individual needs and preferences.\u003c/p\u003e\u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003eThe study data are publicly available on the Open Science Framework (OSF): https://osf.io/bqm9t/\u003c/p\u003e\n\u003cp\u003eFunding declaration: This work was supported by the Faculty of Psychology, University of Warsaw, from the funds awarded by the Ministry of Science and Higher Education in the form of a subsidy for the maintenance and development of research potential (501-D125-01-1250000 zlec. 5011000220).\u003cp\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003e\u0026Aring;dn\u0026oslash;y, T., Solem, S., Hagen, R., \u0026amp; Havnen, A. (2023). An empirical investigation of the associations between metacognition, mindfulness experiential avoidance, depression, and anxiety. 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Retrieved [01.02.2025], from https://www.who.int/news-room/fact-sheets/detail/depression\u003c/li\u003e\n\u003cli\u003eZhang, D., Lee, E. K., Mak, E. C., Ho, C. Y., \u0026amp; Wong, S. Y. (2021). Mindfulness-based interventions: An overall review. British Medical Bulletin, 138(1), 41\u0026ndash;57. https://doi.org/10.1093/bmb/ldab005\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Table numbering","content":"\u003cp\u003eTable numbers 3 and 4 are not used in this version.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"University of Warsaw","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Online Mindfulness-Based Cognitive Therapy, Depression, Internet intervention, Mechanisms of change, iMBCT","lastPublishedDoi":"10.21203/rs.3.rs-7166236/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7166236/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eOnline Mindfulness-Based Cognitive Therapy (iMBCT) is a promising intervention for mental health, but its effectiveness in reducing depressive symptoms remains underexplored. While key mechanisms of change have been identified in traditional MBCT, their role in online delivery formats needs further investigation.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn this randomized clinical trial, 170 individuals with mild to moderate depression were assigned to a 6-week synchronous iMBCT group (n = 58), asynchronous iMBCT group (n = 59), or waitlist control (n = 53). Depression, anxiety, mindfulness, cognitive fusion, rumination, self-compassion, resilience, and experiential avoidance were assessed at baseline, post-treatment, and 3-month follow-up.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ePosttest assessments were completed by 42 participants (72%) in the synchronous group, 32 (54%) in the asynchronous group, and 51 (96%) in the waitlist control condition. Both iMBCT formats significantly reduced depressive symptoms compared to the control group, with sustained effects at follow-up. Mindfulness and cognitive defusion emerged as significant mediators, explaining 52% of the variance in the post-treatment depression severity. Additionally, participants in both interventions showed decreased rumination and anxiety, and increased self-compassion and resilience - effects maintained at follow-up.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSynchronous and asynchronous iMBCT formats are effective in reducing depressive symptoms and enhancing psychological well-being. These findings support the use of online mindfulness-based interventions as scalable, accessible alternatives to traditional therapy.\u003c/p\u003e","manuscriptTitle":"Synchronous online group MBCT vs guided asynchronous iMBCT in depressed sample: randomized clinical trial with a 3-month follow-up","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-07-29 11:25:56","doi":"10.21203/rs.3.rs-7166236/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"99cbed14-eec3-4b95-92da-9845f9b0d4b7","owner":[],"postedDate":"July 29th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":52212559,"name":"Psychology"},{"id":52212560,"name":"Psychiatry"}],"tags":[],"updatedAt":"2025-07-29T11:25:56+00:00","versionOfRecord":[],"versionCreatedAt":"2025-07-29 11:25:56","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7166236","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7166236","identity":"rs-7166236","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}