Chasing the High: Cannabis Mental Health Warning Label Recall is Associated with Greater, Not Lesser, High-Risk Use in a National Canadian Sample

Background: Canada mandates health warning labels on all cannabis products, including a warning linking frequent THC use to long-term mental health problems. Whether exposure to these warnings reduces high-risk use among cannabis consumers remains unknown.Methods: Data were drawn from the 2024 Canadian Cannabis Survey (n=11,666), focusing on 2,197 past-year cannabis users who reported seeing warning messages. Cross-tabulations and chi-square tests tested associations between recall of the THC mental health warning and three outcomes: non-medical daily use, workplace use, and self-reported mental health impact.Results: Among cannabis users who saw warnings, 41.3% recalled the THC mental health warning. Recall was associated with significantly higher rates of non-medical daily use (29.1% vs. 21.9%, p<0.001) and harmful mental health impact (13.0% vs. 7.8%, p<0.001). Among the 264 users who recalled the warning and still used daily, 31.0% reported using cannabis at or before work and 20.8% reported harmful mental health impact — more than double the rate among non-daily users who recalled the warning.Conclusions: The warning label is reaching its intended audience but not changing their behavior. Daily users who recalled the THC mental health warning reported greater harm and higher-risk use patterns than those who did not. Cannabis risk communication may need to move beyond passive product labeling toward interventions that directly address the motivations and contexts driving high-risk use.