Co-use of cannabis and alcohol before and after Canada legalized nonmedical cannabis: A repeat cross-sectional study.

Increases in co-use were observed between 2018 and 2019 in all jurisdictions regardless of the legal status of cannabis. These shifts were largely due to increases in cannabis use across the population, including those that use alcohol, and may indicate changing societal norms toward cannabis generally. As the cannabis legalization transition in Canada matures, evaluation over the longer term will improve understanding of the influence of cannabis liberalization on co-use.