The ARCH Lab collaborated on a study titled “Cannabis Use Frequency and Cannabis-Related Consequences in High-Risk Young Adults Across Cannabis Legalization,” recently published in JAMA Network Open. This longitudinal cohort study examined the impact of recreational cannabis legalization on young adults aged 19.5 to 23, especially those at higher risk due to heavy drinking. The study ran from February 2017 to February 2020 and included 619 participants. Researchers assessed changes in cannabis use and its consequences following legalization.

Authors found:
• Significant decreases in both cannabis use frequency and cannabis-related consequences over time, following recreational cannabis legalization in Canada.
• Changes in cannabis use and consequences were notably influenced by participants’ pre-legalization cannabis use frequency.
• People who used cannabis often before legalization reduced their use and related issues afterward, resembling an “aging out” pattern. On the other hand, those who didn’t use cannabis previously saw a slight increase in use but no corresponding rise in related problems.
• Sex, income, and education did not significantly moderate changes in cannabis use or consequences over the observation period.

The study’s results suggest that recreational cannabis legalization in Canada did not lead to substantive adverse short-term outcomes for high-risk young adults. However, it’s important to note that this study’s design does not rule out the possibility of alternative trajectories in the absence of legalization.