Colombia hosts the largest number of refugees and migrants fleeing the humanitarian emergency in Venezuela, many of whom experience high levels of displacement-related trauma and adversity. Yet, Colombian mental health services do not meet the needs of this population. Scalable, task-sharing interventions, such as Group Problem Management Plus (Group PM+), have the potential to bridge this gap by utilizing lay workers to provide the intervention. However, the current literature lacks a comprehensive understanding of how and for whom Group PM+ is most effective. This mixed methods study utilized data from a randomized effectiveness-implementation trial to examine the mediators and moderators of Group PM+ on mental health outcomes. One hundred twenty-eight migrant and refugee women in northern Colombia participated in Group PM+ delivered by trained community members. Patterns in moderation effects showed that participants in more stable, less marginalized positions improved the most. Results from linear regression models showed that Group PM+-related skill acquisition was not a significant mediator of the association between session attendance and mental health outcomes. Participants and facilitators reported additional possible mediators and community-level moderators that warrant future research. Further studies are needed to examine mediators and moderators contributing to the effectiveness of task-shared, scalable, psychological interventions in diverse contexts.

Background: Forced migration heightens risk of mental health conditions, exacerbated by social protection concerns like gender-based violence (GVB). In Barranquilla, Colombia, we adapted and implemented Group Problem Management Plus (Group PM+), a non-specialist-delivered psychological intervention developed by the World Health Organization (WHO). Venezuelan migrant and Colombian host community women were trained to deliver the program to other women. Although there is evidence on the effectiveness of Group PM+, in depth qualitative explorations may provide insight into associated mechanisms and outcomes. Methods: During phase I, the research team trained community members as Group PM+ facilitators, who delivered the program to 68 women with moderate distress levels. In phase II, participants from phase I were identified to become trainers of new facilitators. A second community-trained cohort, delivered Group PM+ to 59 women. In-depth qualitative data collection and thematic analysis was conducted, employing semi-structured interviews with key informants and focus groups with participants, facilitators and trainers. Results: Facilitators and trainers reported increased self-confidence and empowerment as well as positive impact through community connections, helping others, and personal application of strategies. Challenges included environmental conditions, space availability, and childcare. Group PM+ had significant impact on participants’ lives, particularly in mitigating anxiety, depressive symptoms and in fostering improved community connections and family dynamics. Psychoeducation reduced stigma around depression, relationship issues, and trauma. A widespread wish to continue Group PM+ and expand access to men, domestic partners, and LGBTQ groups was reported. Conclusions: Scalable mental health interventions, like Group PM+, delivered by non-specialists address mental healthcare gaps among displaced populations. Individuals without formal training effectively became facilitators and trainers, highlighting task-sharing importance. Future research should examine the sustainability and scalability costs with minimal non-governmental organization (NGO) or academic support, integration into other community services, and potential long-term benefits of Group PM+ and its interaction with other wellbeing factors.