Systematic Review and Individual Participant Data Meta-Analysis: Reducing Self-Harm in Adolescents: Pooled Treatment Effects, Study, Treatment and Participant Moderators

OBJECTIVE: Self-harm is common in adolescents and a major public health concern. Evidence for effective interventions that stop repetition is lacking. This individual-participant-data (IPD) meta-analysis of randomised controlled trials (RCTs) aimed to provide robust estimates of therapeutic intervention effects and explore which treatments are best suited to different subgroups. METHOD: We searched databases and trial registers, to January-2022. RCTs compared therapeutic intervention to control, targeted adolescents aged 11-18 with a history of self-harm and receiving clinical care and reported on outcomes related to self-harm or suicide attempt. Primary outcome was repetition of self-harm at 12 months post-randomization . Two-stage random-effects IPD meta-analyses were conducted overall and by intervention. Secondary analyses incorporated aggregate data (AD) from RCTs without IPD. PROSPERO registration: CRD42019152119. RESULTS: We identified 39 eligible studies; 26 provided IPD (3,448 participants), 7 provided AD (698 participants). There was no evidence that intervention/s were more or less effective than controls at preventing repeat self-harm by 12 months in IPD (odds ratio (OR)=1.06 [95% CI 0.86, 1.31], studies=20, n=2,949) or IPD+AD (OR=1.02 [95% CI 0.82, 1.27], studies=22, n=3,117) meta-analyses and no evidence of heterogeneity of treatment effects on study and treatment factors. Across all interventions, participants with multiple prior self-harm episodes showed evidence of improved treatment effect on self-harm repetition 6-12 months after randomization (OR=0.33 [95% CI 0.12, 0.94], studies=9, n=1,771). CONCLUSION: This large-scale meta-analysis of RCTs provided no evidence that therapeutic intervention was more, or less, effective than control for reducing repeat self-harm. We observed evidence indicating more effective interventions within youth with two or more self-harm incidents. Funders and researchers need to agree on a core set of outcome measures to include in subsequent studies.