Sustained mental health outcomes from the youth readiness intervention: A four‐year effectiveness follow‐up of a hybrid type <scp>II</scp> trial in Sierra Leone

BACKGROUND: Strategies to expand access to care and sustain evidence-based mental health interventions (EBIs) must be tested within novel delivery platforms to extend the reach of services in fragile and conflict-affected settings. Integration into broader development programs may help maintain long-term effects. This study presents a four-year follow-up of a previously conducted Hybrid Type II implementation-effectiveness cluster-randomized trial (CRT) of the Youth Readiness Intervention (YRI)-an EBI drawing on cognitive-behavioral, interpersonal, and mindfulness-based approaches-delivered within a youth entrepreneurship program in Sierra Leone (2018-2019). METHODS: Long-term mental health outcomes (emotion regulation, psychological distress, and interpersonal functioning) were examined among a randomly selected subgroup of 584 participants across three study arms: a control group, a group that only received entrepreneurship training ('ENTR'), and a group that received both YRI and ENTR ('YRI + ENTR'). Linear mixed-effect models accounted for the nested structure of the data. Impact of the COVID-19 pandemic was also assessed through economic and relationship stressors using structural equation modeling. RESULTS: Four years postintervention, YRI + ENTR-youth maintained improvements in depression (β = -.057; 95% CI -0.09 to -0.02; [effect size] d = -.111) and combined depression/anxiety symptoms (β = -.047; 95% CI -0.08 to -0.01; [effect size] d = -.096) though no sustained effects were observed for daily functioning or emotion regulation. No differences were found for ENTR-only participants versus controls and YRI + ENTR. COVID-19-related economic stressors mediated the relationship between study arm and mental health, revealing small but significant effects. CONCLUSIONS: In low-income settings like Sierra Leone, where formal mental health services are scarce, sustainable community-based interventions such as the combined YRI + ENTR intervention offer a critical approach to reducing psychological distress. Sustained long-term benefits suggest that participants developed coping strategies that supported resilience during challenges like the COVID-19 pandemic. These gains may also foster broader community resilience, enhancing both individual well-being and collective capacity to withstand future adversity.