Changes in population-level alcohol sales after non-medical cannabis legalisation in Canada

There is considerable interest in whether individuals substitute cannabis for alcohol and in legalisation's potential to reduce or increase alcohol-attributable harms. This study aimed to determine whether non-medical cannabis legalisation in Canada was associated with initial changes in population-level alcohol consumption. This observational population-based study described changes in alcohol sales in Canada between 2004 and 2022. We calculated annual changes in the per capita volume of pure ethanol sold in Canada. We used an interrupted time series approach to examine immediate and gradual changes in per capita price-adjusted alcohol retailer sales value (CAD$) and beer producer sales volume (litres of product) after legalisation. During 2004-2022, Canadians aged 15+ spent on average CAD $751 per year on alcoholic beverages containing 8.18 L of ethanol. Annual ethanol sales volumes decreased by 0.06 (95% confidence interval [CI] -0.08 to -0.04; p = 0.001) litres per capita annually for beer but increased by 0.05 (95% CI 0.04 to 0.07; p = 0.001) litres per capita annually for other beverages, leaving no significant trend for ethanol sales overall. Following non-medical legalisation in October 2018, there were no immediate (-0.1%, 95% CI -1.3 to 1.1; p = 0.82) or gradual changes (-0.1% monthly, 95% CI -0.3 to 0.0; p = 0.12) in alcohol retailer sales. Canada's non-medical cannabis legalisation was not associated with significant changes in population-level alcohol sales. These findings do not support the idea that cannabis legalisation may result in declining alcohol use and harms through the substitution of cannabis for alcohol.