Mood in the moment: a study protocol for embedding ecological momentary assessments into established longitudinal cohorts to examine depression in real time

Journal article

Introduction: Depression is a major global health challenge, with onset commonly occurring in youth. There is an urgent need to better understand the epidemiology of depression to facilitate better interventions and preventions that are person-specific and time-specific. Long-term depression trajectories and ecological momentary assessment (EMA) can help address this need. Embedding EMA designs within established longitudinal cohorts offers a uniquely powerful approach to examine depression in both long- and short-term settings and to identify distal and proximal modifiable risk factors for depression.Methods and analyses: Our study will include ~450 participants from the Twins Early Development Study and ~250 participants from the Avon Longitudinal Study of Parents and Children (ALSPAC) who have depression trajectories data previously collected between late childhood and early adulthood. Participants will be recruited from four different depression trajectories in each cohort based on participants’ prior symptoms. They will undertake EMA surveys of depression, sleep, physical activity, substance use, diet, recent activities and social interactions three times a day for 6 weeks, with more detailed questionnaires at baseline, 2, 4 and 6 weeks. We will use descriptive analysis, mixed effects models and dynamic structural equation modelling to examine how depression occurs over this time, how potentially modifiable factors affect depression and vice versa and how these effects vary by different life-course trajectories. This study is designed to identify people at heightened risk of depression and/or identify modifiable targets that could inform more effective prevention and intervention strategies.Ethics and dissemination: Favourable ethical opinions were given by the Edinburgh Medical School Research Ethics Committee (REC References: 25-EMREC-001 and 25-EMREC-030) and the ALSPAC Law and Ethics Committee (Ref: 0027 B4792). The results will be disseminated through journal publications, conferences and seminar presentations and to relevant stakeholders, such as those with a history of depression, policy makers and clinicians

Authors: Kwong, ASF; Moody, S; Taylor, A; Lockhart, C; Ogden, R

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: BMJ Publishing Group
• Journal: BMJ Open More from this journal
• Volume: 16
• Issue: 6
• Pages: e122195-e122195
• Publication date: 2026-06-23
• DOI: 10.1136/bmjopen-2026-122195
• EISSN: 2044-6055
• ISSN: 2044-6055
• Language: English
• Keywords: Avon Longitudinal Study of Parents and Children; depression trajectories; ecological momentary assessment; life course trajectories; adolescent depression; Twins Early Development Study; social interaction; physical activity; depression prevention; substance use; depression; sleep; modifiable risk factors; diet