Abstract
Background
Recovery colleges (RCs) facilitate peer-supported communities where people with lived experience of mental disruption learn collaboratively, aiming to foster empowerment and personal recovery. While existing (qualitative) research relates RC attendance to positive outcomes, high-quality multi-college quantitative studies evaluating RC effectiveness are scarce.
Aims
We examine the extent to which RC attendance impacts empowerment (primary outcome) and other recovery-related outcomes.
Method
In this nonrandomised clinical trial (May 2022 to January 2025), RC partakers from four Dutch RCs were compared with controls over 2 years, in annual data collections. Linear mixed model analyses were conducted to investigate interactions between group and time. Exploratory analyses investigated distinguishing characteristics of RC partakers. This study was embedded in a larger project and was pre-registered (clinicaltrials.gov: #NCT05620212). Academic and experiential researchers collaborated in the design, recruitment, and analysis.
Results
The sample comprised 91 RC partakers and 182 matched controls. RC partakers faced severe or persistent mental health challenges and attended RCs in multiple capacities (e.g., student and visitor/volunteer). Outcomes were mostly stable over time and did not differ between groups. Hence, no group-specific changes over time were found, as shown by interaction terms that were not statistically significant (e.g., empowerment: estimate T1*RC= 0.02, 95% CI= −0.08–0.13, estimate T2*RC= −0.001, 95% CI= −0.11–0.11).
Conclusions
Despite promising qualitative evidence of RC effectiveness, our study found no differences between RC partakers and matched controls in quantitative recovery-related outcomes over time. Factors of influence may be possible pre-study effects, unmeasured confounding, or limitations in how standardised questionnaires capture recovery experiences. Methodologically, the findings raise questions about the operationalisation of effectiveness in the context of personal recovery and flexible, co-created practices such as RCs. Importantly, while this study could not establish measurable effectiveness, this does not automatically imply that RC attendance cannot meaningfully contribute to recovery.
This is a visual representation of the abstract.
Plain Language Summary Title
Study evaluating if recovery colleges have effects on recovery by comparing survey scores of people who do vs. do not attend them across two years
Plain Language Summary
Introduction
Internationally, recovery is increasingly acknowledged within mental healthcare services as an active learning process emphasising empowerment1–4 rather than merely a biomedical process of symptom reduction.
5
Recovery colleges (RCs) illuminate this transformation in mental healthcare, facilitating peer-supported communities where people with lived experience of mental disruption (i.e., peers) collaboratively learn in recovery-related self-help courses, peer-to-peer interactions and volunteering.6–8 RCs are proposed as inspirational examples of recovery-oriented practices5,9,10 and are increasingly implemented worldwide.
11
RC philosophy aligns with an emancipatory movement criticising paternalistic mental healthcare and advocating for centralising lived experiences.12,13 As Patricia Deegan, a lived experience pioneer, described: “Choice, […] role models, […] developing and exercising a voice, opportunities for bettering one's life – these are the features of a human interactive environment that support the transition from not caring to caring, from surviving to becoming an active participant in one's own recovery process”.
14
Initial Evidence
Research on RC effectiveness remains scarce.15–19 High-quality quantitative studies are limited, and existing research often suffers from methodological limitations.15,19,20 To our knowledge, only one pre-post evaluation investigated the effects of RC attendance on empowerment, 21 though several others examined related constructs such as personal recovery22,23 or mental wellbeing,24–26 or evaluated online RC offerings.27,28 These evaluations and qualitative work 29 suggest positive impacts on empowerment. Furthermore, research (predominantly qualitative) relates RC attendance to recovery-related outcomes such as experienced support30,31 and reduced self-stigma.23,30,32 Meta-analyses evaluating courses that many RCs facilitate (e.g., Wellness Recovery Action Planning, WRAP 33 and Honest, Open, Proud, HOP 34 ) also suggest effectiveness. Effects of RC attendance have been suggested to sustain in the long term (e.g., after 1 year 29 ).
This study addresses the call for longitudinal, controlled studies acquiring higher quality evidence of RC effectiveness,15,35 investigating: RQ: Does RC attendance impact empowerment (primary outcome), quality of life, mental health, loneliness, and self-stigma?
Methods
Design
This nonrandomised controlled trial used propensity score matching to approximate conditions of a randomised controlled trial (RCT). 36 RC partakers were compared to matched controls from a large, representative Dutch panel of adults (≥ 18 years) facing severe mental illness (SMI), hereafter “the panel.” 37
Procedure
Data were collected from May 2022 to January 2025, and also served an economic evaluation (under review 20 ). Participants (RC partakers and controls) completed questionnaires online (LimeSurvey) or on paper every 6 months for 2 years, resulting in five assessments. Effectiveness measures for this study were included annually, labelled T0 (baseline), T1 (12 months), and T2 (24 months).
The study builds on a protocol of mixed-methods research on the meaning and effectiveness of RCs 20 (amendments in Appendix A, Table A1). All procedures comply with the Helsinki Declaration of 1975 (revised 2013) and were approved by the Ethics Review Board of Tilburg University (#TSB_RP390). Participants signed informed consent after being briefed. No data was analysed before data collection ended. Reporting follows elements from STROBE 38 and CONSORT 39 guidelines, due to the matched cohort design approximating an RCT.
Academic and experiential researchers (also RC partakers) collaborated throughout the project. 20 Although the role of experiential researchers was more prominent in qualitative studies, they also contributed to the quantitative design, recruitment and interpretation. For this study, a co-research session was hosted to contextualise findings.
Participants and Setting
RCs vary internationally, being mostly co-produced with healthcare providers in Anglophone countries vs. mostly peer-run in the Netherlands. 8 In this study, RC partakers were recruited (on- and offline) at four Dutch RCs (RC1 – RC4). All offered established courses, such as WRAP, and co-created activities. Some RCs facilitated activities at self-managed locations, others in community centres. They also varied in scale (ranging from one to seven locations), organisation (independent foundation, hosted by a mental healthcare or sheltered/supported living organisation) and volunteering opportunities. The four RCs were selected based on expert opinions, were based on similar philosophies, and conformed to the core tasks of Dutch RCs. 8 RC partaker recruitment was terminated when the required sample size of 125 (for a power of 80%) was comfortably achieved. 20 The panel (controls) was always open for registration and actively recruited new members on- and offline, through mental healthcare facilities and community services.
For all participants, received care and support could regard outpatient care (e.g., general practitioner, psychiatrist), inpatient care in (psychiatric) hospitals, community care and/or informal support, with varying frequency and intensity. Some participants did not receive care (anymore).
Group Eligibility
Group eligibility (RC partakers vs. controls) was based on baseline status and not blind. Random allocation was undesirable because it would contradict the open-to-all accessibility of RCs, which emphasises self-chosen attendance. Eligible RC partakers (≥ 18 years) were active at one of the selected RCs at T0 as course students, visitors (of social meeting points), retreat students (taking part in multi-day course with overnight stay), volunteers and/or employees. Eligible controls did explicitly not attend any RC or peer-supported activities at T0 (if they did, they were ineligible for either group and excluded from analysis). Completion of at least the baseline assessment and one follow-up (T1 or T2) was required to be included in data analysis.
Outcomes
All outcomes were self-reported. Empowerment (primary outcome) was measured with three subscales—confidence and purpose, connectedness and self-management—from the Netherlands Empowerment List (NEL 40 ; number of items = 23, αT0= 0.93, αT1= 0.94, αT2= 0.93). Secondary outcomes were quality of life (Maastricht QoL scale 41 ; number of items = 6, αT0= 0.85, αT1= 0.86, αT2= 0.85), mental health (MHI-5 42 ; number of items = 5, αT0= 0.87, αT1= 0.89, αT2= 0.85), loneliness (DeJong Gierveld Loneliness Scale 43 ; number of items = 11, αT0= 0.92, αT1= 0.91, αT2= 0.90) and self-stigma (ISMI-10 44 ; number of items = 10, αT0= 0.76, αT1= 0.80, αT2= 0.72). To compute loneliness scores, dichotomised scores were used; 43 reliability scores were based on the 5-point Likert answers. Internal consistency was acceptable (α ≥ .70) to excellent (α ≥ .90). 45
Matching
Propensity score matching using the nearest neighbour method was performed to account for potential confounding 46 (R package MatchI 47 ). The propensity score was estimated using logistic regression, and participants were matched in a 1:2 ratio without replacement (matching variables: Appendix B, Table B1). To maintain a parsimonious matching model, diagnostic categories were clustered into seven clusters based on clinical similarity (e.g., depression and bipolar disorder grouped as mood disorders) and sample size considerations (e.g., combining disorders with low and comparable frequencies across groups into an “other” category).
Analyses
After matching, linear mixed model analyses were conducted, using R packages lme4 48 and lmerTest. 49 Group, timepoint and their interaction term were added as fixed effects, participant ID as a random effect. If interactions were not statistically significant, a model including main effects of group and timepoint was run. Estimated marginal means (EMMs) were computed to provide model-based averages for each group at each timepoint. These estimates account for the repeated measurements within participants, ensuring fair between-group comparisons across timepoints. Data was analysed based on intention-to-treat. Between-group differences in descriptives were tested using independent samples t-tests or Mann–Whitney U-tests (non-normal data distributions) for continuous variables, and Chi-squared or Fisher's exact tests (if any cell <5 observations) for categorical variables. P-values were corrected for multiple testing using the Holm–Bonferroni procedure, 50 with an adjusted P-value < 0.05 indicating statistical significance. Additionally, effect sizes were computed using Cohen's d 51 to provide information about the magnitude and practical relevance of potential effects, with values of 0.30, 0.50 and 0.80 typically interpreted as small, moderate and large effects, respectively.
Sensitivity and Exploratory Analyses
Mixed models are generally robust to missing data. 52 However, we conducted an imputation-based sensitivity analysis to determine whether conclusions remained consistent regardless of the missing-data approach, using multiple imputation (R package mice 53 ). Additionally, we examined potential confounding by (mental) healthcare use, considering dichotomous mental healthcare use (yes or no) and total healthcare costs at T0. Healthcare costs (in Euros) were indexed to 2022 (the study's starting year); the reference period was 3 months.
Finally, we explored whether RC partakers had different characteristics than those who did not attend an RC, comparing RC partakers with all (including non-matched) eligible controls, using statistical testing of descriptives.
Results
In total, 566 out of 1,769 participants (existing panel members and newly recruited participants) were eligible for inclusion (Figure 1). All 91 RC partakers were matched to 182 eligible controls (38.3% of total 475 eligible controls), composing the definite sample (N= 273).

CONSORT flowchart.
Descriptives
At the study start, participants were 48 years old on average (SD= 12.05) and 75.0% identified as female. Eleven participants reported a gender identity different from their sex. Participants had 2–3 diagnoses of mental disorders on average (M= 2.51, SD= 1.49, Range= 0–7), and 71.4% had more than one. Almost all participants (97.4%) experienced mental health challenges for more than 2 years, 73.3% used psychotropic medication, 9.6% had been admitted in the past 12 months to a psychiatric hospital, and 67.0% used mental healthcare (most prevalent: outpatient mental healthcare clinic [28.2%], Flexible Assertive Community Treatment [18.3%] and private practitioners [16.9%]). About one in four was employed (working 23.84 h per week, SD= 10.66), and 46.5% volunteered (5.99 h per week, SD= 4.27). Post-matching, standardised mean differences (SMDs) between groups (RC – control) were acceptable for all matching variables (<0.10 36 ) except for healthcare costs (SMD= 0.14; descriptives of matching variables in Table 1). Descriptives other than the matching variables are specified per group in Table 2.
Matching Variable Descriptives Pre- and Post-Matching, Including Standardised Mean Differences (SMD) between RC and Control Group.
For SMDs of education, levels else + unknown were combined. RC = Recovery college.
Baseline Descriptives.
Note. NA = not available; FACT = flexible assertive community treatment; RC = Recovery college.
Dropouts
On average, participants completed 2.70 (SD= 0.46) assessments, with 70.3% completing all three (i.e., completers). A Mann–Whitney U-test showed that assessment completion did not differ between RC partakers and controls (MRC= 2.66, Mcontrol= 2.73, W= 7735, P= 0.26). In terms of the matching variables, non-completers reported more “unknown” or “other” education levels (non-completers: 44.4% vs. completers: 3.7%) and less vocational (non-completers: 19.8% vs. completers: 36.5%) or academic (non-completers: 25.9% vs. completers: 44.3%) education levels (χ2 (3)= 71.54, adjusted P<0.001). Missing data per outcome are specified for each timepoint in Table 3.
Estimated Marginal Means (EMM) and Missingness of Primary and Secondary Outcomes by Group at the Three Assessments.
Scores range from 1 to 5, with higher scores indicating better empowerment.
Scores range from 1 to 7, with higher scores indicating better quality of life.
Scores range from 0 to 100, with higher scores indicating better mental health.
Scores range from 0 to 11, with higher scores indicating more loneliness.
Scores range from 1 to 4, with higher scores indicating more self-stigma.
Note. Overall EMMs are based on the LMM with main effects of group and time, EMMs per assessment are based on the LMM with interaction terms included. Model estimates from the LMM with main effects are provided in Appendix D.
RC = Recovery college; LMM = linear mixed model.
Recovery College Attendance
At T0, most RC partakers (62.6%) attended RC1 (vs. RC2: 9.9%, RC3: 14.3%, RC4: 15.4%; two participants attended two RCs). RC partakers were involved as course students (76.9%), visitors (38.5%), volunteers (37.4%), retreat students (23.1%) and/or employees (11.0%). More than half were active in multiple capacities, most frequently as both course student and visitor or volunteer. On average, RC partakers attended the RC 1.78 (SD= 1.16, Range= 1–5) times per week. RC volunteers worked 6.77 h per week (SD= 7.83, Range= 0–44), RC employees worked 16.00 h (SD= 11.3, Range= 1–32) per week. Of the 55 RC partakers who reported the start year of their RC attendance (lower response due to a technical error), more than half (55.9%) had been active at the RC for 0–2 years (of which 6.6% just started), 25.4% had been active for 3–5 years and 11.9% had been active for 6+ years. Some controls also attended an RC during the study (Appendix C, Table C1).
Primary Outcome: Empowerment
Empowerment remained stable for both RC partakers and controls (e.g., RC group: EMMT0= 3.45, EMMT1= 3.52, EMMT2= 3.46; Table 3) and both groups reported comparable levels of empowerment (e.g., on T1, between-group difference in EMMs was 0.15 on a 5-point scale). Hence, there were no group-specific changes over time, as indicated by group-by-time interactions that were not statistically significant (estimate T1*RC= 0.02, 95% CI= −0.08–0.13, estimate T2*RC= −0.001, 95% CI= −0.11–0.11; Table 4).
Results of Linear Mixed Models (Primary and Secondary Outcomes) with Group-by-Time Interaction Effects.
Note. Baseline (T0) and control are references. Statistical significance: adjusted P<0.05. Cohen's d: 0.20 (small), 0.50 (moderate), 0.80 (large).
RC = Recovery college.
Secondary Outcomes
Temporal trends in secondary outcomes also remained stable for both groups (except for a minor, but statistically significant, increase in quality of life at T2 for both groups: Appendix D, Table D1). All group-by-time interaction effects were not statistically significant, indicating that trends over time were similar for both RC partakers and controls (e.g., Quality of life: estimate T1*RC= 0.22, 95% CI= 0.02–0.41, estimate T2*RC= 0.12, 95% CI= −0.09–0.32; Table 4).
Sensitivity Analyses
All sensitivity analyses on imputed data, controlled for baseline dichotomous mental healthcare use (67.0% users vs. 33.0% non-users, comparable ratios in RC and control group) and controlled for total healthcare costs led to similar conclusions (e.g., empowerment in imputed dataset: estimate T1*RC= 0.02, 95% CI= −0.08–0.13, estimate T2*RC= 0.01, 95% CI= −0.10–0.11; all adjusted P's≥ 0.29; Appendix E, Tables E1–3).
Exploratory Analysis: Characteristics of Recovery College Partakers
The exploratory comparison of RC partakers (n= 91) with all eligible pre-matching controls (n= 475), highlighted some differences (Appendix F, Table F1). RC partakers were significantly younger (MRC= 47.84, Mcontrol= 54.03, Mdif= −6.19, 95% CI= −8.77 – −3.62, adjusted P< 0.001), more often reported a diagnosis in the “other” category (RC: 31.9% vs. control: 17.3%, adjusted P= 0.04) and more often volunteered (RC: 58.2% vs. control: 38.7%, adjusted P= 0.02) than pre-matching controls. Of the 53 RC partakers that volunteered, 33 (62.3%) did so at the RC.
Discussion
This is one of the first longitudinal, controlled evaluations of RC effectiveness. Findings showed that temporal trends in self-reported recovery-related outcomes were mostly stable and did not differ for RC partakers and controls. Over the 24-month period, neither group showed significant improvement in empowerment or any of the secondary outcomes (except for a minor significant increase in quality of life, in both groups). While the absence of group-specific changes and improvements overall could suggest a lack of measurable effectiveness, these results should be interpreted in the light of some methodological considerations. For instance, between-group differences may have been attenuated because most RC partakers had already been active in an RC years before baseline, or because both groups received considerable care and support. 54
One longitudinal, matched-controlled evaluation of recovery education centres (REC) offers a partially different perspective. That study reported improvements in empowerment (and mastery) after enrolment, but only among REC participants (vs. controls) who attended at least 14 h during the 12-month study period. 55 Yet, interpreting this finding is not straightforward, as it may reflect (a) a novelty effect, 56 (b) confounding by unmatched variables, such as care use (which was not documented) or level of education (which was higher in the 14+ hours REC group), or (c) a chance finding (due to an increased probability of false positive findings if multiple comparisons are not corrected for50,57). In line with our findings, Durbin et al. 55 found no significant differences between REC partakers and controls on other outcomes.
Although pre- to post-studies21–23 and qualitative inquiries29,35 (including a triangulated qualitative study we conducted in this same setting 58 ) report positive within-person changes in recovery-related outcomes among RC partakers, the broader evidence base suggests that measurable, quantified effects of recovery-oriented interventions are generally small. Both meta-analyses investigating within-person changes in personal recovery (d= 0.34) 59 or between-group effectiveness of peer support (g= 0.15) 60 report small effect sizes that require substantial statistical power to be detected. Furthermore, at a conceptual level, the recovery processes that RCs aim to foster may be challenging to capture through standardised between-group comparisons alone (see Methodological Implications). Taken together, while this quantitative evaluation may not have been able to establish an added measurable effect of RC attendance compared to usual care, this does not rule out that RCs can meaningfully contribute to personal recovery processes.
Practical Implications
Although this study provides no conclusive answers on quantitative RC effectiveness, it offers detailed insights into who attend RCs and in what capacity. Our study's participants faced long-standing and complex mental health challenges, reporting a long duration of experienced mental health problems, comorbidity and substantial care use. RC partakers attended an RC for extended periods and in various roles. Furthermore, RC partakers more often volunteered than comparable individuals facing SMI, especially within the RC, underscoring the potential of RCs as places fostering activation and participation.
Also, RC partakers were younger and more often classified in the “other” diagnostic category, corroborating that some groups may be underrepresented in RCs.61,62 This raises questions about who RCs reach (depending on context), and how the aspired inclusive culture7,8 can be obtained.
Methodological Implications
Our findings prompt critical reflection on how well questionnaires capture experienced recovery. Several scholars suggest that standardised, pre-defined questionnaires might not sufficiently allow nuanced, accurate reports of experiences, for example, because experiences fall between items or are context dependent.63–65 This especially holds for recovery processes, which are non-linear, relational and emergent. Moderate, stable scores as found in our study may therefore reflect averaging, compensatory response strategies of participants to fit complex, erratic experiences into decontextualised ratings, 65 rather than stable recovery or lack of progress. That said, effects on empowerment for people with SMI have been reported, using the same measurement of empowerment as we used (NEL 66 ). As indicated, quantified, measurable effects of RC attendance are likely to be small, and possibly, revealing them requires even larger, more robust designs. In any way, researchers should critically reflect on the extent to which standardised questionnaire responses alone offer accurate insights into lived realities.
Strengths and Limitations
This study stands out for its longitudinal, propensity score-matched design. RCs were evaluated as integral initiatives encompassing various ways of attendance. Panel data access facilitated a large sample of potential controls, enabling precise matching. Despite randomisation being unfeasible within RCs, this procedure resulted in a high-quality evaluation. Furthermore, embedding the study within a larger research project 20 offered access to rich data (e.g., mental healthcare use) and integration of experiential knowledge through the co-created, mixed-methods designs and collaboration with a well-established group of experiential researchers.
These strengths also hold limitations. Approaching the RC integrally meant encountering diverse RC partaking: attendance ranged from 1 to 5 times weekly with many RC partakers combining roles. Activity impact likely varies by context and individual factors 58 (see also in consumer-run organisation context 67 ) and besides that, impacts are expected in various, person-specific domains. This heterogeneity and expected small effect sizes required a substantial sample, but dropouts reduced power and may have introduced selection bias regarding education level. Nonetheless, prior RC studies and experiential researchers’ practice-based familiarity with the RC population supported the sample's representativeness, and attrition rates were relatively small and comparable across groups. Finally, the number of newly engaged RC partakers was smaller than anticipated, and rapid developments of Dutch RCs during the study period may have contributed to controls attending RCs too. The number of known contaminations was small (12 of 182), suggesting that any bias introduced is probably limited. Still, because RC attendance was unknown for part of the control group, some additional contamination cannot be ruled out. Future studies may therefore benefit from larger samples and more strict inclusion criteria to ensure clearer between-group differentiation.
Future Directions
“Effectiveness” in personal recovery, especially within co-created, flexible contexts such as RCs, should be reconsidered. Group-based comparisons may fall short in evaluating how RC attendance can contribute to erratic, meaning-driven recovery processes. Moreover, randomisation contradicts the open-to-all philosophy of RCs. Evaluations of RC effectiveness should accommodate both the individuality of recovery processes and the richness of RC practices.8,68 One promising direction involves conducting large-scale, mixed-methods studies (e.g., diary studies) integrating quantitative and qualitative data, offering deeper understanding of how participants interpret and give meaning to their experiences over time. 64 Given that recovery processes are unique and personal, future research may explore whether incorporating personalised outcome measures (such as goal attainment 69 ) yields additional nuance beyond what standardised measures can capture.
Research should also establish a true baseline by including RC partakers when they start attending, though this is challenging (initial RC attendance can feel overwhelming, limiting research participation). By co-designing studies that are engaging, accessible and low-threshold, together with experiential researchers, studies can better align with participants’ realities. In any way, evaluations should prioritise co-creative methods that integrate experiential knowledge, ensuring that lived experiences shape the design and interpretation of findings. We experienced that this approach fosters richer understanding, more awareness of power dynamics and meaning of evaluations for RC partakers: gains that literature also highlights.17,70
Finally, retrospective analysis of our existing sample could explore heterogeneity. Pairwise comparisons may uncover meaningful change in RC partakers (compared to their matched controls) obscured by aggregated statistics. While avoiding overgeneralising personal recovery processes, exploratory comparisons could yield insights into factors associated with positive outcomes.
Conclusion
Despite the growing body of qualitative evidence suggesting RC effectiveness, our longitudinal, controlled quantitative evaluation did not corroborate this. Empowerment and other recovery-related outcomes were mostly stable over time and did not differ for RC partakers and matched controls. While these findings do not provide measurable support for RC effectiveness, methodological and conceptual considerations caution against drawing definite conclusions. At the same time, detailed insights into who attend RCs (individuals facing severe or persistent mental health challenges) and attendance capacities (in varied roles, mostly for longer periods of time) were acquired. The findings raise questions about how effectiveness can be operationalised in the context of personal recovery and flexible, co-created practices such as RCs, and how evaluative approaches can be refined. Importantly, while this study could not establish a measurable added effect of RC attendance beyond care as usual, this does not rule out that RC attendance can meaningfully contribute to recovery processes.
Footnotes
Acknowledgments
We would like to acknowledge the experiential researchers (POP group) for their vital contribution to the study's design and execution. POP group members (not exhaustive): Annelies Broos, Claartje Bruinsma, Danny van der Spek, Hannah Holleman, Judith Lize, Kelly Leunen, Marieke Cohen, René van der Male. Furthermore, we thank the panel team of the Trimbos Institute for their collaboration in collecting the data: Mark Vergeer, Joyce Huls, Lex Hulsbosch, Aafje Knispel, Bram Zwanenburg, Isabelle Janson, Anne van Jaarsveld. We thank Wouter den Hollander for his input on the study design. Mike Slade acknowledges the support of the NIHR Nottingham Biomedical Research Centre.
Analytic Code Availability Statement
Author Contributions
MW involved in conceptualisation, methodology, data collection, data analysis, writing – original draft, writing—review & editing, and project administration. RS involved in data analysis, and writing – review & editing. CM involved in funding acquisition, conceptualisation, methodology, data analysis, supervision, writing – review & editing, and project administration. BW involved in methodology and writing – review & editing. DM involved in funding acquisition, conceptualisation, methodology, supervision and writing – review & editing. MS involved in writing – review & editing. CH involved in writing – review & editing. HK involved in funding acquisition, conceptualisation, methodology, data analysis, supervision and writing – review & editing. All authors read and approved the final manuscript.
Consent to Participate
Participants provided written informed consent after being briefed.
Data Availability Statement
Declaration of Conflicting Interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Ethical Considerations
The authors affirm that this manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects have been omitted; and that any discrepancies from the planned (and, if applicable, registered) study have been explained. All procedures comply with the Helsinki Declaration of 1975 (revised 2013) and were approved by the Ethics Review Board of Tilburg University (#TSB_RP390).
Funding
The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This research project has been funded by Stichting tot Steun VCVGZ [Foundation to Support VCVGZ] (#289), Gemeente Utrecht [Municipality of Utrecht], and Lister.
ORCID iDs
Appendix
This study was pre-registered in a protocol. 20 In this appendix, we describe which amendments were made to the protocol and why.
Appendix B – Matching Variables
Description of Included Matching Variables.
| Matching Variable | Includes |
|---|---|
| 1. Sex | Sex (female, male, else) |
| 2. Age | Age in years at T0 |
| 3. Origin | Origin (Dutch, non-Dutch, unknown) |
| 4. Level of education | Level of education, with four options: primary and secondary (incl. little to no education, primary school, (lower) pre-vocational secondary education), vocational (incl. senior general secondary education, pre-university education, secondary vocational education), academic (university of applied sciences, university) and else or unknown. |
| 5–11. Diagnoses (seven clusters) | |
| 5. Neurocognitive and developmental disorders | Autism, Attention-Deficit/Hyperactivity Disorder |
| 6. Psychotic disorders | Psychosis, schizophrenia |
| 7. Mood disorders | Bipolar mood disorder, depressive mood disorder |
| 8. Anxiety disorders | Anxiety, obsessive compulsive disorder |
| 9. Trauma and stress | Post-traumatic stress disorder, dissociative identity disorder |
| 10. Personality disorders | Personality disorders |
| 11. Other disorders | Alcohol addiction, substances addiction, behavioural addiction, eating disorders |
| 12. Healthcare costs (€) | Costs of received outpatient care (e.g., general practitioner, psychiatrist), inpatient care in (psychiatric) hospitals, community care, and psychotropic medication. In Euros, indexed to 2022 (study start), the reference period was 3 months. |
Appendix C – Cross-Over Information
Of the RC partakers, 30 were active at one of the selected RCs at all three assessments, others stopped attending or their attendance fluctuated (details on RC attendance among the RC group in Table C1). Among controls, 12 engaged with an RC during the study after T0 (included RC, n= 6, other RC, n= 6) and 12 controls had attended an RC in the 12 months before (but not at) T0 (included RC, n= 7, other RC, n= 5, data on RC attendance was incomplete for 23 controls at T1 and 42 controls at T2).
Appendix D – Results Main Effect Model
Results of Linear Mixed Models with Main Effects of Group and Time.
| Outcome | Estimate | SE | CI 95% | P | Adjusted P | Cohen's D |
|---|---|---|---|---|---|---|
|
|
||||||
| Empowerment | ||||||
| Intercept | 3.32 | 0.05 | 3.23–3.41 | − | − | − |
| Group | 0.13 | 0.08 | −0.01–0.28 | 0.08 | 0.86 | 0.46 |
| T1 | 0.05 | 0.03 | 0.00–0.10 | 0.04 | 0.52 | 0.18 |
| T2 | 0.02 | 0.03 | −0.04–0.07 | 0.58 | 1.00 | 0.05 |
|
|
||||||
| Quality of life | ||||||
| Intercept | 4.46 | 0.08 | 4.30–4.62 | − | − | − |
| Group | 0.02 | 0.14 | −0.24–0.29 | 0.87 | 1.00 | 0.04 |
| T1 | 0.06 | 0.05 | −0.03–0.16 | 0.18 | 1.00 | 0.12 |
| T2* | 0.15 | 0.05 | 0.05–0.24 | 0.003 | 0.04* | 0.28 |
| Mental health | ||||||
| Intercept | 50.01 | 1.38 | 47.31–52.71 | − | − | − |
| Group | 2.65 | 2.24 | −1.74–7.04 | 0.24 | 1.00 | 0.27 |
| T1 | 2.13 | 0.89 | 039–3.87 | 0.02 | 0.22 | 0.21 |
| T2 | 1.22 | 0.92 | −0.59–3.03 | 0.19 | 1.00 | 0.12 |
| Loneliness | ||||||
| Intercept | 6.48 | 0.26 | 5.98–6.98 | − | − | − |
| Group | 0.00 | 0.42 | −0.82–0.82 | 1.00 | 1.00 | 0.00 |
| T1 | −0.04 | 0.17 | −0.36–0.29 | 0.82 | 1.00 | −0.02 |
| T2 | 0.23 | 0.17 | −0.10–0.57 | 0.18 | 1.00 | 0.13 |
| Self-stigma | ||||||
| Intercept | 2.20 | 0.03 | 2.14–2.27 | − | − | − |
| Group | −0.13 | 0.05 | −0.23 – −0.03 | 0.01 | 0.20 | −0.53 |
| T1 | 0.01 | 0.02 | −0.03–0.05 | 0.72 | 1.00 | 0.03 |
| T2 | 0.01 | 0.02 | −0.03–0.05 | 0.65 | 1.00 | 0.04 |
*Statistically significant (adjusted P<0.05). Cohen's d: 0.20 (small), 0.50 (moderate), 0.80 (large).
Appendix E – Results Sensitivity Analyses
Results of Linear Mixed Models (Primary and Secondary Outcomes) with Group-by-Time Interaction Effects Controlled for Healthcare Use Costs (at T0).
| Original | Controlled for Healthcare Use Costs | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Outcome | Estimate | SE | CI 95% | Estimate | SE | CI 95% | P | Adjusted P | Cohen's d |
|
|
|||||||||
| Empowerment | |||||||||
| Intercept | 3.32 | 0.05 | 3.23–3.41 | 3.36 | 0.05 | 3.26–3.45 | − | − | − |
| T1*RC | 0.02 | 0.06 | −0.08–0.13 | 0.02 | 0.06 | −0.08–0.13 | 0.66 | 1.00 | 0.08 |
| T2*RC | −0.001 | 0.06 | −0.11–0.11 | −0.001 | 0.06 | −0.11–0.11 | 0.99 | 1.00 | 0.00 |
|
|
|||||||||
| Quality of life | |||||||||
| Intercept | 4.50 | 0.08 | 4.33–4.66 | 4.54 | 0.09 | 4.36–4.72 | − | − | − |
| T1*RC | 0.22 | 0.10 | 0.02–0.41 | 0.22 | 0.10 | 0.02–0.41 | 0.03 | 0.29 | 0.42 |
| T2*RC | 0.12 | 0.10 | −0.09–0.32 | 0.12 | 0.10 | −0.09–0.32 | 0.26 | 1.00 | 0.22 |
| Mental health | |||||||||
| Intercept | 50.17 | 1.42 | 47.39–52.94 | 51.59 | 1.50 | 48.64–54.54 | − | − | − |
| T1*RC | 1.48 | 1.89 | −2.22–5.18 | 1.47 | 1.89 | −2.23–5.17 | 0.44 | 1.00 | 0.15 |
| T2*RC | −0.07 | 1.97 | −3.94–3.80 | −0.07 | 1.97 | −3.94–3.80 | 0.97 | 1.00 | −0.01 |
| Loneliness | |||||||||
| Intercept | 6.41 | 0.26 | 5.90–6.93 | 6.31 | 0.28 | 5.76–6.87 | − | − | − |
| T1*RC | −0.19 | 0.35 | −0.88–0.50 | −0.19 | 0.35 | −0.88–0.50 | 0.59 | 1.00 | −0.10 |
| T2*RC | −0.48 | 0.37 | −1.20–0.24 | −0.48 | 0.37 | −1.20–0.24 | 0.19 | 1.00 | −0.26 |
| Self-stigma | |||||||||
| Intercept | 2.21 | 0.03 | 2.14–2.27 | 2.17 | 0.03 | 2.10–2.24 | − | − | − |
| T1*RC | 0.01 | 0.05 | −0.08–0.09 | 0.01 | 0.05 | −0.08–0.09 | 0.90 | 1.00 | 0.02 |
| T2*RC | 0.03 | 0.05 | −0.06–0.13 | 0.03 | 0.05 | −0.06–0.13 | 0.47 | 1.00 | 0.14 |
Note. Baseline (T0) and control are references. RC= Recovery college.
Appendix F – Results Exploratory Analysis
Descriptives of RC Partakers vs. Pre-Matching Controls (N= 566).
| RC Partakers (n= 91) | Pre-Matching Controls (n= 475) | Test | Test Statistic | ΔM (95% CI) | P | Adjusted P | |
|---|---|---|---|---|---|---|---|
| n (%) | n (%) | t or χ2 | |||||
| Matching variables | |||||||
|
|
Fisher exact |
|
|
0.02 | 0.24 | ||
| Female | 69 (76) | 316 (66) | |||||
| Male | 21 (23) | 159 (34) | |||||
| Else | 1 (1) | 0 | |||||
|
|
Independent samples T-test | −4.76 | −6.19 (−8.77 – −3.62) | < 0.001 | <0.001 | ||
| Mean (SD) | 47.84 (11.28) | 54.03 (11.85) | |||||
| Range | 23–73 | 23–83 | |||||
| Unknown | 0 | 5 | |||||
|
|
Chi-squared | 2.76 | - | 0.10 | |||
| Dutch | 69 (78) | 400 (86) | |||||
| Non-Dutch | 19 (22) | 65 (14) | |||||
| Unknown (NA) | 3 (-) | 10 (-) | |||||
|
|
Chi-squared | 5.08 | - | 0.17 | 1.00 | ||
| Primary or secondary | 13 (17) | 103 (24) | |||||
| Vocational | 29 (38) | 168 (39) | |||||
| Academic | 34 (44) | 153 (35) | |||||
| Else | 1 (1) | 11 (3) | |||||
| Unknown (NA) | 14 (-) | 40 (-) |
| RC Partakers (n= 91) | Pre-Matching Controls (n= 475) | Test | Test Statistic | ||||
|---|---|---|---|---|---|---|---|
| n (%) | n (%) | t or χ2 | ΔM (95% CI) | P | Adjusted P | ||
|
|
|||||||
| Neurocognitive developmental disorders | 29 (32) | 103 (22) | Chi-squared | 3.88 | - | 0.05 | 0.54 |
| Psychotic disorders | 13 (14) | 128 (27) | Chi-squared | 5.89 | - | 0.02 | 0.21 |
| Mood disorders | 54 (59) | 279 (59) | Chi-squared | 0.00 | - | 1.00 | 1.00 |
| Anxiety disorders | 33 (36) | 163 (34) | Chi-squared | 0.06 | - | 0.81 | 1.00 |
| Trauma and stress | 39 (43) | 131 (28) | Chi-squared | 7.77 | - | 0.005 | .10 |
| Personality disorders | 35 (39) | 114 (24) | Chi-squared | 7.51 | - | 0.006 | .10 |
| Other disorders* | 29 (32) | 82 (17) | Chi-squared | 9.43 | - | 0.002 | .04 |
|
|
Independent samples T-test | 1.20 | 527.07 |
0.23 | 1.00 | ||
| Mean (SD) | 2,287 (3,821) | 1,760 (3,957) | |||||
| Range | 0–27,261 | 0–55,937 | |||||
| OTHER DESCRIPTIVES | |||||||
|
|
Fisher exact | - | - | 0.16 | 1.00 | ||
| Female | 56 (73) | 166 (60) | |||||
| Male | 18 (23) | 99 (36) | |||||
| Non-binary | 1 (1) | 3 (1) | |||||
| Else | 1 (1) | 9 (3) | |||||
| Rather not say | 1 (1) | 2 (1) | |||||
| Unknown (NA) | 14 (-) | 196 | |||||
|
|
Independent samples T-test | 2.54 | 0.44 (0.10–0.79) | 0.01 | 0.18 | ||
| Mean | 2.55 | 2.11 | |||||
| SD | 1.55 | 1.39 | |||||
| Range | 0–7 | 0–6 | |||||
| #N More than 1 | 67 (74) | 289 (61) |
| RC Partakers (n= 91) | Pre-Matching Controls (n= 475) | Test | Test Statistic | ΔM (95% CI) | P | Adjusted P | |
|---|---|---|---|---|---|---|---|
| n (%) | n (%) | t or χ2 | |||||
|
|
Fisher exact | - | - | 0.61 | 1.00 | ||
| < 1 year | 1 (1) | 16 (3) | |||||
| 1–2 years | 0 (0) | 3 (1) | |||||
| > 2 years | 87 (99) | 441 (96) | |||||
| Unknown (NA) | 3 (-) | 15 | |||||
|
|
Chi-squared | 8.25 | - | .004 | .08 | ||
| Yes | 59 (65) | 376 (79) | |||||
| No | 32 (35) | 98 (21) | |||||
| Unknown (NA) | 0 (-) | 1 (-) | |||||
|
|
Chi-squared | 7.31 | - | .007 | .11 | ||
| Yes | 69 (76) | 286 (60) | |||||
| No | 22 (24) | 189 (40) | |||||
|
|
Chi-squared | 4.67 | - | .03 | .37 | ||
| Yes | 12 (13) | 29 (6) | |||||
| No | 79 (87) | 445 (94) | |||||
| Unknown (NA) | 0 (-) | 1 (-) | |||||
|
|
Chi-squared | 0.00 | - | 1.00 | 1.00 | ||
| Yes | 18 (20) | 93 (20) | |||||
| No | 73 (80) | 378 (80) | |||||
| Unknown (NA) | 0 (-) | 4 (-) | |||||
|
|
Independent samples T-test | −1.55 | −4.28 |
0.13 | 1.00 | ||
| Mean | 22.33 | 26.61 | |||||
| SD | 10.66 | 11.14 | |||||
| Range | 4–40 | 2–64 |
| RC Partakers (n= 91) | Pre-Matching Controls (n= 475) | Test | Test Statistic | ΔM (95% CI) | P | Adjusted P | |
|---|---|---|---|---|---|---|---|
| n (%) | n (%) | t or χ2 | |||||
|
|
Chi-squared | 11.15 | - | <0.001 | .02 | ||
| Yes | 53 (58) | 184 (39) | |||||
| No | 38 (42) | 291 (61) | |||||
|
|
Independent samples T-test | −1.09 | −0.90 |
0.28 | 1.00 | ||
| Mean | 6.19 | 7.09 | |||||
| SD | 4.60 | 7.20 | |||||
| Range | 0–20 | 0–60 |
