Exploring the context, mechanisms, and outcomes of school-based group interpersonal therapy for depressed adolescents in Nepal: Analysis of qualitative process data from a pilot realist cluster-randomized controlled trial

OBJECTIVE: Evidence-based psychotherapies constitute first-line treatments for youth depression, yet their effects remain modest and largely unchanged over the past three decades. A critical gap persists in understanding how and for whom these therapies work. Realist trials address this gap by iteratively developing and testing context-mechanism-outcome configurations (CMOC) within randomized controlled trials (RCTs). As an initial step in that process, this study reports on qualitative research embedded in a pilot realist cluster RCT of group interpersonal therapy (IPT) for depressed adolescents in Nepal. METHODS: Semi-structured interviews and focus groups were conducted with 41 participants purposively sampled across four schools. Data were analyzed thematically, guided by realist principles. RESULTS: Findings highlighted key mechanisms: improved emotion regulation and problem-solving skills, reduced interpersonal conflict, closer relationships, and increased self-efficacy. Contextual factors appeared to interact with these mechanisms: adolescents from lower socioeconomic backgrounds were perceived to benefit more due to greater motivation. The experience of adversity was viewed to alter how mechanisms operated. Sharing feelings openly appeared critical for group IPT to work. CONCLUSION: Findings align with previous work and suggest different mechanisms might be at play for different groups. The refined CMOCs will be quantitatively tested in a forthcoming phase 3 realist RCT.