Canadian Cannabis Use Slightly Rises While Misuse Declines Post-Legalization

Since recreational cannabis was legalized in Canada in October 2018, researchers from McMaster University have observed a modest uptick in how often adults use cannabis, along with a notable decrease in misuse over a five-year period. The study indicates that while the overall frequency of cannabis use increased marginally, adults who were frequent users before legalization experienced the largest reductions in problematic use and frequency.

The research, published in JAMA Network Open, involved 1,428 participants aged 18 to 65 from Ontario, who completed biannual online assessments from September 2018 through October 2023. Cannabis use frequency was quantified by the percentage of days individuals used cannabis over six months, while misuse was evaluated through an eight-item questionnaire assessing dependence, control issues, and adverse impacts.

Findings revealed a 0.35% annual increase in the percentage of days cannabis was used, accumulating to a 1.75% rise over five years. Conversely, misuse scores showed a steady decline of 0.08 points annually, totaling a 0.4 point decrease over the same period, with notable reductions observed after the COVID-19 pandemic onset. The study also noted shifts in product preference, moving away from dried flower, hashish, and concentrates towards edibles, liquids, and vape pens.

Importantly, the results suggest that legalization did not lead to widespread increases in cannabis misuse or usage, providing some reassurance about its long-term impact. However, the researchers highlight that continued monitoring is essential to better understand long-term effects.

Overall, the study underscores a nuanced picture: modest increases in use coupled with improvements in use behavior, indicating that regulatory measures may help mitigate potential risks associated with increased access.

Source: https://medicalxpress.com/news/2025-05-canadian-cannabis-climbs-slightly-curbing.html