Adolescent talking therapies for low-resource settings: Asking what works for whom, how, and in what circumstances

Worldwide, depression is common among adolescents and can have detrimental effects on their health and development. In high-income countries adolescents with depression can be treated with evidence-based interventions including talking therapies such as cognitive behaviour therapy and interpersonal therapy (IPT). These therapies are generally unavailable in low- and middle-income countries (LMICs) where 90% of the world's adolescents live. Researchers have tried with varying success to take therapies developed in high-income countries and adapt them for LMICs. A major barrier to implementing therapies in different settings is that we do not know much about how they work, who they work for, where they work best and over what time frame. Answering these questions is key to advancing the field of global mental health and is therefore the focus of my FLF. I will test IPT, a talking therapy with the potential to improve adolescent depression in LMICs. To do this I will conduct a realist randomised controlled trial (RCT). This is an innovative approach that combines testing intervention mechanisms and modifying effects of contextual factors with an evaluation of the overall intervention impact. I will also address the lack of longitudinal research on depression in LMICs through a longer term follow-up of trial participants. Through a personalised training programme and international placements, I aim to develop as an intervention scientist, impact champion and mental health advocate, whilst also working to build the capacity of early career researchers involved in the project through training and mentorship. I will test IPT in Nepal, a low-income country where I have strong collaborations and in 2018-20 led a UKRI-funded study that adapted and showed the feasibility of school-based group IPT for depressed adolescents aged 13-18. I will use my work in Nepal as a springboard for the fellowship and later broaden my focus to other LMICs. The first phase of my FLF (Years 1-5 of a 5[+3 year] FLF model adjusted for part-time working) involves: i) Development of an IPT logic model to map all the potential inputs and outcomes of IPT, mechanisms of change, and contextual factors that modify the mechanisms and effects of the intervention. I will do this through stakeholder consultation (adolescents, Nepali and international mental health specialists), consolidating psychological and social theory on IPT through a desk review, and integrating findings from my earlier IPT adaptation and feasibility study. ii) Testing short and medium-term effects of IPT by conducting a realist RCT in Nepal. This will involve collecting qualitative and quantitative data from adolescent participants aged 13-18 and key stakeholders. I will use the data to assess IPT's impact and cost-effectiveness, and to refine and test hypotheses informed by the IPT logic model about intervention mechanisms and outcomes and how they vary by context (rural/urban, school environment) and participant characteristics (caste/ethnicity, age, gender). In preparation for the RCT I will develop and test procedures for data collection and control and intervention conditions through a small pilot trial. In the second phase (Years 6-8) I will explore longer term effects of IPT and adolescent depression through a mixed methods follow-up study of RCT participants. I will assess participants 18 and 30 months after the intervention to examine whether outcomes are maintained and knock-on consequences for health, education, employment, and relationships. Data will also help to answer broader, elusive questions including: what are the mechanisms of relapse and remission in adolescent depression?; how does depression in early adolescence influence health and socio-economic trajectories in later adolescence and young adulthood? I will collaborate with the Identifying Depression Early in Adolescence (IDEA) Research Consortium to synthesise data from Nepal and cohorts in other LMICs.