Canadian study shows link between cannabis legalization and increase in road accidents

The results of a recent study published in JAMA Network Open claim to have found a link between the legalization of cannabis and an increase in road accidents.

The study was conducted by researchers at the University of Ottawa and examined emergency room visits in Ontario, Canada, over a 12-year period (January 2010 to December 2021), at the end of which they noted a 475.3 % increase in car accidents that resulted in an emergency room visit in which the driver had to cannabis in the body at the time of the accident.

«This cross-sectional study revealed a sharp increase in the involvement of cannabis in emergency room visits for motor vehicle accidents over time, which may have accelerated following the commercialization of cannabis for non-medical purposes,» reads the conclusion of the study. «Although the frequency of visits is rare, they may reflect broader changes in cannabis-impaired driving. Greater prevention efforts, including targeted education and policy measures, in areas where cannabis is legal are indicated.»

At first glance, 475.3 % is a large number. However, the study was only conducted in Ontario, Canada. The total number of cannabis-related injury accidents during this 12-year period was 426 out of 947,604, or 0.04%.

«One another study also found no increase in the number of of the total number of hospitalizations for road accidents in Canada in the 2.5 years following legalization. It is critical to note that the slow rollout of the retail cannabis market in Canada and the overlap of the legalization period with the COVID-19 pandemic significantly reduce the ability of these studies to assess the impacts of legalization,» the study states.

The study did, however, highlight the fact that men appear to be more at risk than women of being involved in such accidents when cannabis intoxication is considered a factor.

«Of the 418 individuals with documented cannabis involvement, 330 (78.9 %) were male, 109 (25.6 %) were aged 16 to 21 years (mean [SD] age at visit, 30.6 [12.0] years), and 113 (27.0 %) had had an emergency department visit or hospitalization for substance use in the two years prior to their emergency department visit for a motor vehicle accident,» the study states.

«The results of this repeated cross-sectional study suggest that cannabis-related serious traffic accidents have increased over time. Legalization of cannabis for non-medical purposes, widespread access to retail sales and an increase in the variety of cannabis products may have increased these visits despite laws specifically aimed at deterring driving under the influence of cannabis,» the study states.

«Young adults and men appear to be at particularly high risk of cannabis-related road accidents. There may be a need for intensified interventions, including cannabis-impaired driving education, enforcement activities and policies to regulate access to commercial retail markets.»