Exploring Naturalistic Diffusion of an Evidence-Based Mental Health Intervention across Peer Networks of Youth in Sierra Leone

Background: Understanding the mechanisms by which evidence-based interventions (EBIs) for mental health are naturally diffused among youth in low-and middle-income countries—particularly those with histories of violence and civil unrest—can illuminate which intervention elements are most transferrable and inform scale-up decisions that support youth adjustment. This study explored the diffusion of an evidence-based mental health intervention—the Youth Readiness Intervention (YRI)—among peer networks of Sierra Leonean youth (aged 18–30) who participated in a trial of the intervention as integrated into youth entrepreneurship programs. Methods: Trained research assistants recruited index participants who had completed the YRI integrated within entrepreneurship training (N = 165) and control index participants (N = 165). Index participants nominated three of their closest peers. Nominated peers were recruited and enrolled in the current study (N = 289). A sub-sample of index participants and peers participated in dyadic interviews (N = 11) and focus group discussions (N = 16). Multivariate regression analysis compared YRI knowledge levels among YRI participants’ peers relative to control participants’ peers. Results: Qualitative findings supported the diffusion of several YRI skills and components across peer networks (i.e., progressive muscle relaxation and diaphragmatic breathing). Quantitative findings indicated that YRI knowledge was significantly higher for YRI participants’ peers (β = 0.02, p < 0.00) compared to control participants’ peers. Conclusion: Findings suggest that diffusion of evidence-based intervention components can occur naturally among peers in post-conflict LMIC settings. Developing tools to promote the diffusion of the most transferrable EBI components across peer networks could help maximize the benefits of mental health interventions for youth adjustment and resilience in post-conflict settings.