An overview of the adverse effects of cannabis use for Canadian physicians

Cannabis is the most widely used illicit substance and one of the most commonly used psychoactive substances in the world, preceded only by alcohol, tobacco and caffeine. Recent changes in legislation regarding cannabis use in Canada and potential upcoming changes worldwide may have a further impact on the prevalence of cannabis use. Thus, it is critical to understand the risks and potential adverse health effects of acute and long-term cannabis use. Current literature is lacking in many areas surrounding cannabis use, and for the most part is unable to provide clear associations once confounding variables are considered. Here we provide a general overview of the history of cannabis, the physical and mental health consequences, and the risks to specific groups.