Background The Canadian government legalized non-medical cannabis use by adults in October 2018 to minimize associated harms and redirect profits from criminals. In October 2019, a wider array of products, including edibles, was legalized, with entry into the legal market beginning in December. Data and methods Three quarters (the first quarters of 2018 and 2019 and the fourth quarter of 2020) of the National Cannabis Survey were used to examine changes in cannabis use (overall use and daily or almost daily (DAD) use), consumption methods, products and sources. Results Cannabis use in the past three months was higher in late 2020 (20.0%) than in 2019 (17.5%) and 2018 (14.0%), and this was particularly the case among: females (for whom rates rose to equal male rates for the first time), adults aged 25 and older, and some provinces. Similarly, DAD use, at 7.9% also increased. Higher percentages of Canadians reported getting at least some of their cannabis from legal sources or growing it, and fewer were relying on friends and family or illegal sources in 2020. Interpretation This study spans three years-from before legalization to about two years after. It provides a more complete picture of the law's impact on cannabis use and related behaviours, given the more established legal cannabis industry better equipped to compete with the black market on price, convenience and selection. Findings demonstrate that change is continuing, and, as before, some cautions and assurances remain. The impact of the COVID-19 pandemic on cannabis use continues to be difficult to measure. Monitoring remains important, given the ever-changing provincial retail landscapes; the introduction of new products; and the pressure by the industry to remove or adjust potency limits, and allow widespread delivery, farm-gate sales and cannabis lounges.
