Impact of the Sources of Strength Peer Leader Program on Suicide Attempt Rates in 40 High Schools: A Cluster...

Universal interventions are essential to reduce suicide rates. This study describes a hybrid effectiveness-implementation cluster RCT of Sources of Strength, a program that prepares diverse student peer leaders to disseminate a healthy coping framework. Forty predominantly small-town and rural high schools (four serving American Indian Nations and federal reservations) were randomized to Sources of Strength for 2 years or wait-list. Of 21,053 students, 17,280 participated in ≥ 1 of four waves. Students reported on suicide attempts and theory-informed mediators. Sources of Strength did not reduce suicide attempts overall, and impact differed by implementation quality and grade. Sources of Strength increased communication and help-seeking from adults in year 1, with findings supporting an indirect program effect reducing suicide attempts through increased adult help with emotions. However, declining implementation adherence in year 2, particularly in messaging activities, coincided with loss of impact. Program benefits were not found for 9th graders. In schools with poor adherence including deviation from peer leader selection guidelines, 9th graders showed increased new suicide attempts vs. controls. From this and other trials combined-including a recent trial showing program impact reducing suicide attempts among 9th-11th graders-we conclude that Sources of Strength implemented with strong adherence can reduce suicide attempts through its theoretical pathway of increased protective adult relationships. However, implementation drift eliminates those benefits. Poor adherence to messaging and peer leader selection may accelerate negative peer influences and increase risk particularly for younger students. Findings underscore the critical importance of maintaining fidelity in peer-based prevention programs. Trial registration at ClinicalTrials.gov #NCT02043093, 01/23/2014.

The online version contains supplementary material available at 10.1007/s12310-025-09802-w.