Effectiveness of suicide prevention interventions: A systematic review and meta-analysis

Objective: This study provides an estimate of the effect size of suicide prevention interventions and evaluates the possible synergistic effects of multilevel interventions. Method: A systematic review and meta-analysis were conducted of controlled studies evaluating suicide prevention interventions versus control published between 2011 and 2017 in PubMed, PsycINFO, and Cochrane databases. Data extraction and risk of bias assessment according to ROBINS criteria were performed by independent assessors. Cohen's delta was calculated by a random meta-analysis on completed and attempted suicides as outcomes. Meta-regression explored a possible synergistic effect in multilevel interventions. PROSPERO ID number: CRD42018094373. Results: The search yielded 16 controlled studies with a total of 252,932 participants. The meta-analysis was performed in 15 studies with 29,071 participants. A significant effect was found for suicide prevention interventions on completed suicides (d = -0.535, 95% CI -0.898; -0.171, p = .004) and on suicide attempts (d = -0.449, 95% CI -0.618; -0.280, p < .001). Regarding the synergistic effect of multilevel interventions, meta-regression showed a significantly higher effect related to the number of levels of the intervention (p = .032). Conclusions: Suicide prevention interventions are effective in preventing completed and attempted suicides and should be widely implemented. Further research should focus on multilevel interventions due to their greater effects and synergistic potential. Further research is also needed into risk appraisal for completed versus attempted suicide, as the preferred intervention strategy differs with regard to both outcomes.