Female youth reported more cannabis use by 2023 in Ontario

BACKGROUND AND AIMS: Cannabis use has historically been more prevalent among men and boys compared with women and girls, yet growing evidence has suggested a recent narrowing of the sex/gender gap. Our goal was to examine changes in the sex gap in cannabis use, harms and perceptions in Ontario, Canada. DESIGN, SETTING AND PARTICIPANTS: Observational study using data sourced from the Ontario Student Drug Use and Health Survey (OSDUHS; 1999-2023), a biennial, cross-sectional, population-based, school-based survey of students in Ontario, Canada (n&#x2009;=&#x2009;106&#x2009;815). MEASUREMENTS: Our exposure measure was sex at birth (binary male/female measure). Outcomes included indicators of use (cannabis use initiation before Grade 9, cannabis use during the past month, daily cannabis use during the past month and cannabis use during the past 12&#x2009;months), indicators of harms (cannabis dependence symptoms during the past 3 months and driving after using cannabis during the past 12&#x2009;months) and perceptions (perceived ease of obtaining cannabis and perceived great risk of harm associated with regular cannabis smoking). Male-to-female ratios (MFRs) of the prevalence of these outcomes were calculated, with trends analyzed using joinpoint regression. An MFR&#x2009;<&#x2009;1 indicated that the outcome is higher in females. RESULTS: Most indicators of cannabis use decreased overall among male and female youth. MFRs statistically significantly decreased between 1999 and 2023 for cannabis use during the past month [Average Biennial Percentage Change: -1.4, 95% confidence interval (CI) = -2.4 to -0.3], daily cannabis use during the past month (-6.3, 95% CI = -10.0 to -2.4) and cannabis use during the past 12&#x2009;months (-2.6, 95% CI = -4.5 to -0.6), with all indicating a higher prevalence among female youth compared with male youth in 2023 (though these were higher in male youth in nearly all other years). A similar trend was found for perceived ease of obtaining cannabis (-1.2, 95% CI = -1.9 to -0.5), whereas MFRs for perceived great risk of harm associated with regular cannabis smoking, cannabis use initiation before Grade 9, cannabis dependence symptoms during the past 3 months and driving after using cannabis during the past 12&#x2009;months did not statistically significantly change and were higher among males compared with females between 1999 and 2023. SUMMARY: The sex ratio in prevalence of cannabis use appears to have declined among Ontario youth from 1999 to 2023, indicating greater prevalence of cannabis use among female youth in recent years, though this trend needs to be replicated with future data waves.