Among 35,000 Ontario teens, the cannabis-distress association grew stronger over a decade, especially for frequent female users, possibly reflecting rising THC potency.
Adolescent mental health professionals; cannabis policy researchers; parents.
Heavy use-distress gap: 0% in 2013, 18% in 2023
What the researchers found
Distress rose from 10.7% to 27.4% while cannabis use declined from 23.1% to 17.6%. Heavy use (40+ times) vs abstinence: adjusted prevalence difference went from 0% (2013) to 18% (2023). Dose-response in females but not males. Each later grade of initiation: 5% lower distress.
Why it matters
The strengthening association despite declining use rates is consistent with rising potency driving more harm per user. The female dose-response is a new prevention-relevant finding.
The numbers in context
35,007 students. Distress: 10.7% to 27.4%. Cannabis use: 23.1% to 17.6%. Heavy use-distress difference: 0% (2013) to 18% (2023). 5% lower distress per later grade of initiation.
How the study worked
Representative biennial surveys 2013-2023 in Ontario. 35,007 students grades 7-12. Modified Poisson regression with Kessler-6.
What this study cannot tell us
Cross-sectional at each wave. Cannot determine causation direction. Rising distress has many causes. Self-reported.
How to read the evidence
Large representative survey spanning 10 years with 35,000+ students.
When this study was published
2026 study
The bigger picture
Cannabis potency has increased substantially. The parallel strengthening of the cannabis-distress link despite declining use supports the potency hypothesis.
Questions still open
- Is rising potency driving this? Are females more biologically vulnerable? Would potency limits help?
Common questions
Why is the association strengthening if fewer teens use?
Why does age of initiation matter?
Read the original research
Adolescent cannabis use and psychological distress from 2013 to 2023: A population-based study in Ontario, Canada.
Addiction (Abingdon, England)
Citation
McDonald, André J; Doggett, Amanda; Bondy, Susan J; Colman, Ian; Cook, Steven; Hamilton, Hayley A; Kurdyak, Paul; Leatherdale, Scott T; Myran, Daniel T; Rehm, Jürgen; Wickens, Christine M; MacKillop, James; Halladay, Jillian. (2026). Adolescent cannabis use and psychological distress from 2013 to 2023: A population-based study in Ontario, Canada.. Addiction (Abingdon, England). https://doi.org/10.1111/add.70333
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