Prevalence and correlates of selling illicit cannabis among people who use drugs in Vancouver, Canada: A ten-year prospective cohort study

Background: The illicit selling and use of cannabis is prevalent among marginalized people who use illicit drugs (PWUD). Given that participation in illicit drug markets has been previously associated with a range of health and social harms, we sought to examine the predictors of selling cannabis among PWUD in Vancouver, Canada, a setting with a de facto legalized cannabis market, on the eve of the planned implementation of legalized nonmedical cannabis including measures to regulate the existing illicit market. Methods: Multivariable generalized estimating equations (GEE) logistic regression was used to analyze longitudinal factors associated with selling illicit cannabis among three prospective cohorts of PWUD between September 2005 and May 2015. Results: Among the 3258 participants included in this study, 328 (10.1%) reported selling illicit cannabis at baseline, and 46 (5.1%) initiated cannabis selling over the study period. In the multivariable analysis of the whole sample, factors significantly associated with selling cannabis included cannabis use (Adjusted Odds Ratio [AOR] = 4.05), dealing other drugs (AOR = 3.87), being male (AOR = 1.83), experiencing violence (AOR = 1.40), non-medical prescription opioid use (AOR = 1.32), non-custodial involvement in the criminal justice system (AOR = 1.31), being stopped by police (AOR = 1.30), crack use (AOR = 1.25), homelessness (AOR = 1.23), age (AOR = 0.96 per year) and participation in sex work (AOR = 0.67) (all p < 0.05). The subanalyses indicated that dealing drugs other than cannabis, cannabis use, and non-custodial involvement in the criminal justice system were the only factors significantly associated with selling cannabis in all four subgroups. Conclusion: These findings support existing evidence indicating that selling illicit cannabis is often a survival driven strategy to support the basic needs and substance use of some PWUD. Our findings suggest jurisdictions with planned or impending cannabis legalization and regulation should consider the vulnerability of PWUD when seeking to eradicate illicit cannabis markets, for example, in setting criminal penalties for selling cannabis outside of regulatory frameworks.