1 Département des sciences de la santé communautaire, Université de Sherbrooke, 2500, boul. de l'Université, Sherbrooke, Québec, J1K 2R1, Canada; Centre de recherche Charles-Le Moyne, 150 Place Charles-Le Moyne, Longueuil, Québec, J4K 0A8, Canada.
2 Department of Psychology, Concordia University, 7141 Sherbrooke West, Montreal, Québec, H4B 1R6, Canada.
3 Alberta's Tomorrow Project, Cancer Research & Business Partnerships, Cancer Care Alberta, 1820 Richmond Road SW, Calgary, Alberta, T2T 5C7, Canada.
4 Département des sciences de la santé communautaire, Université de Sherbrooke, 2500, boul. de l'Université, Sherbrooke, Québec, J1K 2R1, Canada; Centre de recherche Charles-Le Moyne, 150 Place Charles-Le Moyne, Longueuil, Québec, J4K 0A8, Canada. Electronic address: helen-maria.vasiliadis@usherbrooke.ca.

Aims: This study identified sex-specific multi-trajectories of anxiety and depression symptoms among Canadians before and during the COVID-19 pandemic, and associated factors according to a public mental health framework for the surveillance of mental health.

Methods: Data from 15,021 participants in the Canadian Partnership for Tomorrow's Health cohort, collected in 2018, 2020, 2021, and 2022, were analyzed. Anxiety and depression symptoms were assessed using the GAD-7 and PHQ-8 scales. Group-based multi-trajectory modeling identified distinct patterns of joint symptom evolution in males and females. Multinomial logistic regression analyses examined associations between trajectory groups and individual, living environment, and global/system level factors.

Results: Four anxiety-depression multi-trajectory groups were identified in females and males: resilient (26.6%, 37.0%), persistent minimal fluctuating (49.0%, 42.4%), persistent mild fluctuating (20.0%, 17.6%), and persistent moderate fluctuating (4.4%, 3.0%). Trajectory forms differed by sex, with males showing greater variation. Compared to the resilient group, membership in the three symptom trajectories was associated with individual (e.g., younger age, lower household income, multimorbidity, lifetime presence of a mental disorder), living environment (e.g. emotional/psychological support), and global/system level (e.g., reduced wages/h of work, barriers to mental health care) factors.

Conclusions: These findings highlight inequities in mental health and access to care, calling for targeted clinical follow-up of individuals with pre-existing mental disorders, as well as public health campaigns and health policies aimed at reducing barriers to accessing mental health services.