WED-112 - Marijuana Legalization and Opioid Use Disorder in Ontario, Canada, from 2015 to 2021

Brief Abstract Summary: Discover the relationship between cannabis legalization and opioid-related harms in Ontario Canada. This study analyzed opioid-related hospitalizations and deaths in Ontario, Canada, from March 2015 to March 2021, focusing on trends before and after cannabis legalization. Data on opioid-related deaths and hospitalization obtained from the CIHI Databases were analyzed using the generalized estimation equation (GEE) method. GEE analysis indicated a significant increase in monthly hospitalizations during the legal cannabis period (B = 61.99, p < 0.001) and yearly rises in opioid-related deaths from 2017 to 2021. This study challenges the prevailing assumption that increased cannabis legalization would mitigate opioid misuse and its associated harms. The worsening trend in opioid-related harm shown during the cannabis legal period supports the claim that cannabis may be a gateway drug.

Detailed abstract description: This study examined the trends in opioid-related hospitalizations and deaths in Ontario, Canada, from March 15, 2015, to March 15, 2021, with a particular focus on the periods before and after cannabis legalization. The social problem addressed was the ongoing opioid crisis, exacerbated by rising opioid-related health issues. Grounded in the harm reduction theory, this research explored whether cannabis legalization could serve as a substitute to mitigate opioid use disorder.

Data were extracted from the Discharge Abstract Database, Emergency Department Database, National Ambulatory Care Reporting System, and Hospital Morbidity Database.

Analysis using the generalized estimation equation (GEE) method revealed a significant increase in opioid-related hospitalizations, which rose from a mean of 405.56 (SD = 38.67) in 2015 to 1486.33 (SD = 49.803) in 2021, representing 366% increase. The hospitalization rate notably increased twofold in 2020 and threefold in 2021 compared to 2015. A one-way ANOVA demonstrated a statistically significant effect of time on both hospitalizations, F(6,65) = 37.67, p < 0.001, and deaths, F(6,65) = 8.67, p < 0.001. The GEE analysis indicated a significant rise in monthly hospitalizations from the illegal to the legal cannabis period (B = 61.99, SE = 6.37, p < 0.001), along with significant yearly increases in opioid-related deaths from 2017 to 2021.

These findings suggest that opioid-related health issues intensified during the cannabis legalization era, though the specific impact of the COVID-19 pandemic on these trends remains unclear. The study’s implications for social change include insights into the potential role of cannabis legalization as a harm reduction strategy, which could inform policies aimed at addressing the opioid crisis.