Adolescence is a key period of development for mental health; however, little is known about how (cumulative) daily life experiences impact long-term mental health development in this period, and vice versa. ‘Mental health in the moment’ (MHIM) is an accelerated cohort measurement burst study designed to illuminate these links.

The current protocol describes the rationale and design for MHIM, which aims to recruit and follow up approximately 500 adolescents across five age cohorts (in secondary school years S1–S5, aged 11–16 at baseline) and follow them over a 5-year data collection period. Data collection will include online surveys and ecological momentary assessments bursts every 6 months, annual caregiver surveys, the collection of stress biomarker data at three key measurement points and continuous radar-based sleep measurement for a subsample of participants. The study is informed by a young person advisory group input throughout its lifecycle. Data will be analysed using techniques such as dynamic structural equation modelling. The study can provide insights into mental health development from a multitimeframe developmental perspective, including insights into ‘daily life’ intervention targets for improving adolescent mental health.

The study received ethical approval from the philosophy, psychology and language science ethics committee at the University of Edinburgh (404-2425/3) and the findings will be published in a series of peer-reviewed publications.