Long-term health outcomes of adolescent character strength interventions: 3- to 4-year outcomes of three randomized controlled trials of the Shamiri program

BACKGROUND: Adolescents in low- and middle-income countries in need of mental health care often do not receive it due to stigma, cost, and lack of mental health professionals. Culturally appropriate, brief, and low-cost interventions delivered by lay-providers can help overcome these barriers and appear effective at reducing symptoms of depression and anxiety until several months post-intervention. However, little is known about whether these interventions may have long-term effects on health, mental health, social, or academic outcomes. METHODS: Three previous randomized controlled trials of the Shamiri intervention, a 4-week, group-delivered, lay-provider-led intervention, have been conducted in Kenyan high schools. Shamiri teaches positively focused intervention elements (i.e., growth mindset and strategies for growth, gratitude, and value affirmation) to target symptoms of depression and anxiety and to improve academic performance and social relationships, by fostering character strengths. In this long-term follow-up study, we will test whether these mental health, academic, social, and character-strength outcomes, along with related health outcomes (e.g., sleep quality, heart-rate variability and activity level measured via wearables, HIV risk behaviors, alcohol and substance use), differ between the intervention and control group at 3–4-year follow-up. For primary analyses (N(anticipated) = 432), youths who participated in the three previous trials will be contacted again to assess whether outcomes at 3–4-year-follow-up differ for those in the Shamiri Intervention group compared to those in the study-skills active control group. Multi-level models will be used to model trajectories over time of primary outcomes and secondary outcomes that were collected in previous trials. For outcomes only collected at 3–4-year follow-up, tests of location difference (e.g., t-tests) will be used to assess group differences in metric outcomes and difference tests (e.g., odds ratios) will be used to assess differences in categorical outcomes. Finally, standardized effect sizes will be used to compare groups on all measures. DISCUSSION: This follow-up study of participants from three randomized controlled trials of the Shamiri intervention will provide evidence bearing on the long-term and health and mental health effects of brief, lay-provider-delivered character strength interventions for youth in low- and middle-income countries. TRIAL REGISTRATION: PACTR Trial ID: PACTR202201600200783. Approved on January 21, 2022. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13063-022-06394-7.