Cannabis Use and Cannabis Use Disorder: Burden of Disease in Canada, Trends in Utilization of Specialized Addiction Treatment Services in Ontario and Efficacy of Brief Interventions

Three broad topics related to the treatment of cannabis use and cannabis use disorder were examined. First, cannabis-attributable burden of disease in Canada in 2012 was quantified based on the burden of disease analyses, including comparative risk assessments. The cannabis-attributable burden of disease was substantial, most of it due to cannabis use disorder in the form of disability rather than mortality. Although the contributions of cannabis-attributable schizophrenia, lung cancer and road traffic injuries were comparatively minimal, lung cancer and road traffic injuries were the main contributors to cannabis-attributable mortality. Second, trends in treatment of problematic cannabis use were characterized through Ontario’s specialized addiction treatment system between 2010/11 and 2015/16. As cannabis use became less stigmatized and more accepted as normative behavior, clients in treatment for problematic cannabis use only decreased. At the same time, the frequency of cannabis use among all clients in treatment for problematic cannabis use increased. Taken together, treatment that was unnecessary from a clinical standpoint may have been reduced, but there may have been overall increases in severity. Third, the efficacy of brief interventions for cannabis use, compared with minimal control interventions, was reviewed based on participants recruited from health care settings in randomized trials. A systematic review and meta-analyses indicated an overall small number of studies on this topic. The available evidence indicated that brief interventions for cannabis use were not efficacious for improving cannabis-specific ASSIST scores and number of days of cannabis use. On the other hand, the evidence for other cannabis-specific outcomes was limited and mixed. Altogether, the three studies suggested continued monitoring of cannabis use disorder, continued public education of lower risk cannabis use, lack of evidence to scale up brief interventions for cannabis use, expansion of treatment options for cannabis use disorder and development of the evidence base for cannabis use.Ph.D