Changes in Cross-Sectional Associations Between Cannabis Use and Anxiety, Depression, and Suicidality in a Nationally Representative Sample of Canadians From 2012 to 2022: Évolution des relations transversales entre la consommation de cannabis et la dépression, l’anxiété et les idées suicidaires au sein d’un échantillon représentatif de Canadiens à l’échelle nationale, de 2012 à 2022

ObjectiveAs epidemiological patterns of cannabis use and internalizing problems evolve globally, it is critical to reassess their associations-particularly in the post-legalization and post-pandemic context.MethodsParticipants were assessed in the 2012 Canadian Community Health Survey's Mental Health Component (CCHS-MH; n = 25,113) and 2022 Mental Health and Access to Care Survey (MHACS; n = 9,861), two nationally representative cross-sectional epidemiologic surveys of Canadians aged 15+. Robust Poisson Regression analyses examined associations between frequency of cannabis use and past 12-month generalized anxiety disorder (GAD), major depressive episode (MDE), and suicidality assessed using the World Health Organization Composite International Diagnostic Interview.ResultsBetween 2012 and 2022, the prevalence of GAD, MDE, and cannabis use (any and 2+/week) approximately doubled, while suicidality remained unchanged in the full sample but increased by 44% among youth. Across all models, cannabis frequency was consistently associated with a higher prevalence of GAD, MDE, and suicidality in a frequency-dependent fashion. Additive interactions between year and cannabis on each of the outcomes demonstrated stronger associations in 2022 versus 2012. For example, from 2012 to 2022, those using cannabis 2+/week (relative to no use) had a: (1) prevalence ratio (PR) for GAD of 2.3 (95% CI, 1.6-3.4) increase to 4.5 (3.8-5.2); (2) PR for MDE of 3.0 (2.3-3.9) increase to 5.2 (4.6-5.7); and (3) PR for suicidality of 3.0 (2.1-4.0) increase to 5.4 (4.7-6.1). Select moderation effects indicated associations between cannabis and MDE or suicidality strengthened more among youth (15-24 vs. 25+), and associations with GAD strengthened more among females.ConclusionsCannabis use was consistently related to a higher prevalence of internalizing problems, and these associations strengthened between 2012 and 2022. Given continued escalations in co-occurring cannabis use and internalizing problems, greater investment in early identification, intervention, and access to integrated substance use and mental health treatment is needed.