The Canadian Journal of PsychiatryChanges in Cross-Sectional Associations Between Cannabis Use and Anxiety, Depression, and Suicidality in a Nationally Representative Sample of Canadians From 2012 to 2022

A nationally representative Canadian study found cannabis use frequency consistently associated with GAD, MDD, and suicidality in a dose-response pattern that strengthened significantly between 2012 and 2022. Canadians using cannabis 2+ times weekly in 2022 were roughly 5 times more likely to report an internalizing disorder than non-users, nearly doubling the association seen a decade earlier.

Clinical Considerations

• Number needed to harm dropped sharply: for MDE, from 14 in 2012 to 7 in 2022 among those using cannabis 2+ times weekly
• Youth suicidality increased 44% between 2012 and 2022, with cannabis associations for MDE and suicidality strengthening more among adolescents than adults
• Female patients showed stronger cannabis-GAD associations over time; sex-specific screening may be warranted
• Cross-sectional design limits causal inference; residual confounding and increased THC potency may contribute to strengthened associations

Practice Applications

• Screen all patients with GAD, MDE, or suicidality for cannabis use frequency, not just use status
• Counsel patients that frequency matters: risks escalate sharply above once-weekly use
• Prioritize cannabis screening in youth and female patients given disproportionate risk signals
• Integrate substance use and mental health treatment pathways for patients with co-occurring cannabis use and internalizing disorders

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