Cannabis use and co‐use in tobacco smokers and non‐smokers: prevalence and associations with mental health in a cross‐sectional, nationally representative sample of adults in Great Britain, 2020

Background and aims In Great Britain, cannabis tobacco are commonly used substances, both independently together. Use of either substance is associated with mental health problems, but prevalence co-use within these populations unknown. We aimed to (1) estimate use, frequency use routes administration (ROA) among smokers non-smokers (2) investigate problems non-users, tobacco-only, cannabis-only co-users substances. Design Cross-sectional national on-line survey (Action on Smoking Health) fielded in February–March 2020. Setting Britain. Participants Adults Britain aged ≥ 18 years (n = 12 809) Measurements Tobacco status [smoker (daily or non-daily) non-smoker (never ex-smoker)], daily), detailed ROAs cannabis, self-reported treatment for disorders (depression, anxiety any). Statistically weighted estimates were computed ensure representativeness. Correlates assessed using χ2 tests logistic regression. Findings 2020, 7.1% the sample had past year. greater odds year (21.9%) daily (8.7%) than [past-year: 4.7%; adjusted ratio (aOR) 10.07, 95% confidence interval (CI) 8.4–12.0; daily: 0.7%; aOR 24.6, CI 18.0–33.6)]. Co-administration was common (46.2% non-smokers, 80.8% smokers). Co-users reported highest any (54.2%) comparison (45.8%), tobacco-only (33.2%) non-users (22.7%; all P ≤ 0.05). Conclusion Approximately one 13 adults reports having year, approximately four times as many cigarette non-smokers. tobacco, via smoking, appears be common, including self-identified Mental appear particularly dual users.