[The data and metadata repository of the Québec Mental Health Alliance].

Objectives In the era of artificial intelligence, our understanding of mental health challenges depends heavily on our ability to generate and analyze large-scale datasets. Accordingly, the Data Valorization Axis of the Québec Mental Health Alliance (ASMQ) was established in 2024 to create a comprehensive repository of open mental health data and metadata in Québec. This initiative's mandate is to facilitate the indexing and discoverability of data and metadata collected in Québec, notably at the 3 main mental-health research centers of the Fonds de recherche du Québec: the Centre de recherche de l'Institut universitaire en santé mentale de Montréal (CR-IUSMM), the Centre de recherche CERVO and the Centre de recherche Douglas. Methods To build the Alliance repository, researchers and clinicians at ASMQ affiliated institutions were directly invited to index the datasets available in their laboratories. Nine databases were identified, and some are currently accessible via online-sharing platforms: Neurobagel, Maelstrom, and the Atlas of Longitudinal Datasets. Here, we present a description of the data contained in the various databases. Results To date, the data and metadata of 11,570 participants (26% psychosis and schizophrenia, 21% personality disorder, 19% mood disorder, 12% substance use, 10% bipolar disorder, 9% anxiety disorder) across 8 biobanks and datasets have been shared online through the Alliance repository. The biobank metadata includes various demographic (e.g. age, sex, gender, level of education), medical (e.g. psychiatric and physical diagnoses, medication use), psychosocial (e.g. social functioning, quality of life, depressive symptoms), anthropometric (e.g. height, weight), metabolic, behavioral (e.g. sleep, consumption of non-food products), cognitive (e.g. performance on neurophysiological tests), and medical-imaging data. Additionally, general information on governance and procedures for accessing and contributing new data to the repository is provided. Impact The Québec Mental Health Alliance repository enhances the visibility and accessibility of mental-health data in Québec, facilitating the sharing and dissemination of domain-specific data and metadata. The repository also aims to facilitate the harmonization of access procedures and experimental protocols. By advancing open science in Québec, the Alliance repository can catalyze scientific breakthroughs that rely on the analysis of large-scale datasets. This initiative could eventually be extended to other health institutions across Québec.