Zach Walsh University of British Columbia This study examined the use of cannabis as a substitute for alcohol and other psychoactive drugs among medical cannabis users with and without histories of substance use treatment. The aim of this study was to examine the stability of the substitution effect with regard to treatment history among medical cannabis users. Substance use among medical cannabis users: Substituting cannabis for alcohol and other substances -Findings indicate that cannabis use is perceived to substitute for alcohol and other drugs among users of cannabis for therapeutic purposes -Clinical implications for those undergoing treatment for problematic alcohol and illegal drug use -Findings that substitution was generally consistent across illnesses and among those with and without treatment histories suggests good generalizability of substitution effects -Highlights importance of research on interaction of cannabis use with other psychoactive substances This study is a part of the larger Cannabis Access for Medical Purposes Survey (CAMPS), the largest and most comprehensive polling of Canadian medical cannabis patients to date. Participants: 470 self-selected Canadian adults who endorsed current medical cannabis use. Measures: Participant completed online or in- person survey that queried attitudes and behaviors associated with medical cannabis use, substance use treatment history, and substitution of cannabis for alcohol and/or illicit drugs. Psychoactive/pharmacological substitution occurs when the availability of one substance affects the use of another (Hursh et al., 2005). Among cocaine-dependent patients receiving addictions treatment, moderate cannabis use was associated with higher retention rates than cannabis abstainers, suggesting cannabis may provide an effective substitute (Aharonovich et al., 2006). In a sample of over 400 medical cannabis (MC) patients, approximately 75% report substituting cannabis for another substance (e.g., alcohol, illicit drugs, prescription drugs; Lucas et al., 2012). Approximately 40-50% MC patients substitute cannabis for alcohol, and 25-50% substitute cannabis for illegal drugs (Lucas et al., 2012; Reiman, 2009) It appears that cannabis may provide an alternative for potentially more harmful substances, and as such may have a place in harm-reduction strategy. INTRODUCTION METHODS Aharonovich, E., Garawi, F., Bisage, A., Brooks, D., Raby, W. N., Rubin, E., Nunes, E. V., & Levin, F. R. (2006). Concurrent cannabis use during treatment for comorbid ADHD and cocaine dependence: Effects on outcome. The American Journal of Drug and Alcohol Abuse, 32, Hursh, S. R., Galuska, C. M., Winger, G., & Woods, J. H. (2005). The economics of drug abuse: A quantitative assessment of drug demand. Molecular Interventions, 5, Lucas, P., Reiman, A., Earleywine, M., McGowan, S. K., Oleson, M., Coward, M. P., & Thomas, B. (2012). Cannabis as a substitute for alcohol and other drugs: A dispensary-based survey of substitution effect in Canadian medical cannabis patients. Addiction Research and Theory, 1-8. Reiman, A. (2009). Cannabis as a substitute for alcohol and other drugs. Harm Reduction Jounral, 6(35). DISCUSSION REFERENCES ABSTRACT CONTACT -55.7% (N=262) report using cannabis as a substitute for alcohol and/or illegal drugs -Past/current treatment for substance use reported by 15.7% (N=74) -Patients with treatment histories were more likely to substitute cannabis for illegal drugs than those without treatment history (X 2 = 33.55, p <.01) -Patients with no treatment history were more likely to substitute cannabis for alcohol (X 2 = 6.00, p <.05) - Rates of substitution were consistent across primary illness, with the exception that MS patients reported significantly lower rates of substitution (X 2 = 5.68, p <.05) RESULTS FINANCIAL SUPPORT This research was supported by a grant to Dr. Zach Walsh from the University of British Columbia Institute for Healthy Living and Chronic Disease Prevention P. Lucas 1, K. Crosby 2, Z. Walsh 2 R. Callaway, L. Belle-Isle 1, R. Capler 2, S. Holtzman 2, B. Kay 3 1. Centre for Addictions Research of British Columbia, 2. University of British Columbia. 3. Green Cannapy Research and Development, Kelowna, BC