Feasibility, Acceptability and Potential Efficacy of the Group Problem Management Plus Intervention among adults in Kenya: A quasi-experimental study

Aims: The burden of common mental disorders (CMDs) is high in Kenya. Unfortunately, most Kenyans (75%) in need of mental healthcare cannot access these services. This study evaluates the feasibility, acceptability, and effectiveness of a brief, lay provider-delivered group-based psychological intervention, Group Problem Management Plus (gPM+) among adults with moderate symptoms of CMDs in a Kenyan urban informal settlement. Methods: In this quasi-experimental pre-post study, 274 adults (63.5% females) in Changamwe sub-county in Mombasa were identified through screening of depressive symptoms (the 9-Item Patient Health Questionnaire, PHQ-9), anxiety symptoms (the 7-Item Generalized Anxiety Disorder Questionnaire, GAD-7) and symptoms of post-traumatic stress disorder - PTSD (the Primary Care PTSD Screen for DSM-5, PC-PTSD-5). gPM+ comprised of 5 weekly group sessions with eight to twelve participants per group. The intervention was delivered by 10 trained non-specialist facilitators from a local civil society organization between August 2024 and April 2025. Primary outcomes were scores on PHQ-9, GAD-7 and PC-PTSD-5 assessed at baseline, 2 weeks, 5 weeks and 3 months follow-up. Secondary outcomes included functional impairment, self-identified problems, self-perceived social support, self-perceived wellbeing, and a measure of gPM+ acceptability, feasibility and appropriateness. Results: 428 participants were screened for eligibility, of whom 274 (64%) participated in gPM+ at baseline and there were 241 (88.0%) participants at 3-months follow-up. The findings demonstrated that lay facilitators from a grassroots organization can be trained to achieve the desired competency to effectively implement gPM+ in an urban informal settlement under supervision. Overall, there was a good intervention uptake, with gPM+ considered appropriate and useful by participants and lay facilitators. Relative to baseline, the outcome evaluation indicated that at follow-up there was a statistically significant reduction in symptoms of depression anxiety and PTSD. We also observed statistically significant improvements in all secondary outcomes. Conclusion: This formative study demonstrated robust acceptance of gPM+ in the community settings with delivery by lay facilitators under supervision. Preliminary evidence shows that gPM+ has the potential to improve the mental health and wellbeing of adults in urban informal settlements in Kenya. The study sets the stage for further exploration of the outcomes through large scale implementation and definitive randomised controlled trials in the community.