Effectiveness and implementation outcomes for peer-delivered mental health interventions in low- and middle-income countries: a mixed-methods systematic review

Purpose This review aimed to evaluate interventions led by peer counselors (PCs) for adults with common mental disorders in low- and middle-income countries (LMICs) along indices of overall effectiveness and key implementation outcomes (acceptability, feasibility, cost, fidelity, sustainability). Methods This review followed a mixed-methods systematic review design. MEDLINE/PubMed, Embase, PsycINFO, and Global Health databases were searched for PC-led interventions for adults in LMICs targeting depressive and/or anxiety disorders or PTSD. Quantitative data was narratively synthesized, and qualitative data was thematically synthesized separately. The results from the qualitative and quantitative syntheses were then combined in a cross-study synthesis. Results Twenty-four papers describing thirteen PC-led interventions were included for review. Narrative synthesis results indicated mixed effectiveness of PC-led interventions in reducing depressive, anxiety, PTSD symptoms and high PC competency. Thematic synthesis revealed five descriptive themes: (1) Preferred PC characteristics; (2) Incentives and motivation for PCs; (3) Barriers to PC-led intervention implementation; (4) Helpful supervision/training practices; and (5) Overall high acceptability of PC-led interventions. Cross-study synthesis revealed high acceptability, feasibility, and fidelity, but cost and sustainability outcomes were underreported in included papers. Conclusion PC-led interventions seem to show initial promise in terms of effectiveness, acceptability, feasibility, cost, fidelity, and sustainability. Future research should focus on standardizing measurements of implementation outcomes to facilitate cross-study analysis. Additional empirical attention should be paid to underrepresented implementation outcomes (e.g., cost, sustainability). Finally, researchers should adopt a participatory approach that elevates the perspectives of PCs throughout all stages of the implementation process.

Automated summary

This review evaluated interventions led by peer counselors for adults with common mental disorders in low- and middle-income countries. The results indicated mixed effectiveness of these interventions in reducing symptoms, with high acceptability. Factors and barriers related to the implementation were also identified. However, there was limited reporting on cost and sustainability outcomes.