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Landscaping International Longitudinal Datasets

The Wellcome Trust commissioned the Landscaping International Longitudinal Datasets project in September 2022 to conduct a global mapping of large-scale longitudinal datasets with the potential for transformative research on depression, anxiety and psychosis. The partnership that undertook this project was comprised of an academic institution (King’s College London), a charity (MQ Mental Health Research), a non-profit organisation (Open Data Institute) and lived experience expert (LEE) group, all of whom worked with a range of national and international collaborators. Further input from various stakeholders was gathered as part of dissemination activities and a Theory of Change (ToC) process throughout the project.

The scope of this project was four-fold. First, to search for and identify longitudinal datasets worldwide and across sectors on mental health or any other topics. Second, to describe richness across all identified longitudinal datasets. Third, to review ongoing studies with large sample sizes, granular assessments and mental health data collected (or could be collected) on participants aged between 14 and 30 years. Fourth, to present areas that could be enriched via new data collection or recruitment of participants.

The project identified more than 3,000 longitudinal datasets across the world. During the landscaping process the team discovered richness for mental health research in several longitudinal datasets that we organised into 19 groups or ‘pockets of value’. These pockets were then clustered into four categories:

  • Richness in mental health measures
  • Value in targeted populations
  • Diversity of data
  • Mental health embedded in wider context

The review also indicated a shortage of ongoing studies with large sample sizes, granular assessments and mental health data when participants are between 14 and 30 years. A further review revealed opportunities for enrichment covering four areas:

  • Preservation and expansion of targeted populations
  • Improvement of measurement and collection of new data
  • Build infrastructure and facilitate connectivity
  • Promotion of LEE involvement, community engagement and service users’ input

The Landscaping project’s global search for longitudinal datasets and in-depth analysis of their potential for mental health research revealed great opportunities for researchers and funders to build knowledge that can improve our understanding of depression, anxiety and psychosis. A coordinated approach to funding longitudinal research and a resolute will to enhance the discoverability of existing datasets will maximise the financial, time and resource investment made thus far.


Alice Stephens, research assistant

Daniel Yu, undergraduate placement student

Thomas Canning, research assistant