Identification of cannabinoids in post-mortem blood samples from the province of New Brunswick before and after recreational cannabis legalization.

Abstract

Since recreational legalization of cannabis in Canada in 2018, self-reported use in New Brunswick (NB) has increased from 15.1% to 20.3%, the largest increase of any province. Current literature on the impact of recreational cannabis legislation in other jurisdictions is conflicting, though retail availability has often been delayed on enactment. Given the immediate availability of cannabis in NB after legalization, we sought to establish the effect this had on post-mortem cannabinoid detection. Furthermore, we wanted to investigate the impact that age, sex, and manner of death had on cannabis use. We also established if there were any increases in commonly detected drugs over the study period. A retrospective chart review was conducted on all adult Coroner's cases with toxicology analysis in NB between January 2014 and May 2020 (n=3060). Differences in the proportion of cannabinoid-positive samples pre- versus post-legalization in the overall cohort as well as within each demographic parameter were assessed using chi-square tests. The effects of demographic parameters on cannabis presence were further assessed by logistic regression. Lastly, chi-square tests for trend were performed to identify increasing trends in cannabis detection, as well as cocaine, ethanol, opiates/opioids, benzodiazepines, and amphetamines over the study period. After controlling for age, sex, and manner of death, participants that died after recreational legalization had higher odds of having cannabis present post-mortem than those that died pre-legalization. In addition, demographic sub-analysis identified a greater proportion of cannabinoid-positive samples post-legalization in 25- to 44-year-olds and in deaths classified as either suicide or accidental compared to pre-legalization. We also observed a significant increase in the presence of cocaine and amphetamines in post-mortem samples over the study period. This study demonstrates that cannabis use has increased post-legalization in NB, particularly within young adults and those dying by suicide or accidental means. It also highlights the need for future research into the impact that legalization has on cannabis use in other jurisdictions.