Might cannabis Legalization Have Affected Public Health-Relevant Alcohol- and Tobacco-use Outcomes in Canada?

Canada legalized the non-medical use and supply of cannabis in 2018. The public health-relevant outcomes of cannabis legalization documented to date have been mixed, with decreases in cannabis-related crime and illegal distribution markets, while with increases for many - acute and chronic - health problem indicators. One public health-relevant aspect of legalization that has not been adequately assessed to date are its potential effects on alcohol and/or tobacco use and related outcomes in the population. Existing literature suggests that cannabis legalization may impact alcohol and/or tobacco use in different ways and directions, through both 'substitution'- and/or 'complementarity'-type dynamics. While cannabis use prevalence has markedly increased through legalization, recent epidemiological indicators suggest the possibility of (small) changes in rspective other substance use, yet it is empirically unclear whether these developments are causally interrelated. Also considering the substantial adverse public health burden arising from alcohol and tobacco use in the Canadian population, this Commentary makes the case for systemic examination of the potential impacts of cannabis legalization on alcohol and/or tobacco use outcomes by way of rigorous analytical methods as part of assessing the overall public health-related effects of cannabis legalization in Canada as well as other jurisdictions where cannabis has been legalized.