Is the Individual the Clue in Prevention? Towards a New Personalised Understanding of Depression Prevention in Adolescents (360G-Wellcome-335218_Z_25_Z)

Depression rates among adolescents and young adults have risen over the past two decades. Depression is difficult to treat, often requiring intensive intervention, and even then, relapse and recurrence mean the lives of those with first-onset depression may be permanently affected. This highlights the urgent need for effective onset prevention. However, efforts to develop such strategies have been limited, with some school-based interventions worsening symptoms. A key barrier is the lack of intensive, longitudinal research capturing the dynamic, person-specific processes that drive depression onset and how they can be targeted. Promising insights may come from integrating approaches from successful relapse-prevention interventions targeting similar mechanisms. Therefore, the aims of this study are to: 1. Identify person- specific psychological and behavioural risk processes contributing to depression onset. 2. Determine promising psychological intervention components targeting these processes. 3. Test whether these components modify risk processes and reduce depression risk. This research will use Ecological Momentary Assessment in a representative youth cohort to identify real-time predictors of first-onset depression. A component network meta-analysis and Delphi survey will isolate effective components, informing a conceptual framework for personalised prevention, to be tested in a randomised A-B-A design. Findings will inform personalised, evidence-based strategies to prevent youth depression.