Substituting cannabis for prescription drugs, alcohol and other substances among medical cannabis patients: The impact of contextual factors

Drug Alcohol Rev. 2016 May;35(3):326-33. doi: 10.1111/dar.12323. Epub 2015 Sep 14.


Introduction and aims: Recent years have witnessed increased attention to how cannabis use impacts the use of other psychoactive substances. The present study examines the use of cannabis as a substitute for alcohol, illicit substances and prescription drugs among 473 adults who use cannabis for therapeutic purposes.

Design and methods: The Cannabis Access for Medical Purposes Survey is a 414-question cross-sectional survey that was available to Canadian medical cannabis patients online and by hard copy in 2011 and 2012 to gather information on patient demographics, medical conditions and symptoms, patterns of medical cannabis use, cannabis substitution and barriers to access to medical cannabis.

Results: Substituting cannabis for one or more of alcohol, illicit drugs or prescription drugs was reported by 87% (n = 410) of respondents, with 80.3% reporting substitution for prescription drugs, 51.7% for alcohol, and 32.6% for illicit substances. Respondents who reported substituting cannabis for prescription drugs were more likely to report difficulty affording sufficient quantities of cannabis, and patients under 40 years of age were more likely to substitute cannabis for all three classes of substance than older patients.

Discussion and conclusions: The finding that cannabis was substituted for all three classes of substances suggests that the medical use of cannabis may play a harm reduction role in the context of use of these substances, and may have implications for abstinence-based substance use treatment approaches. Further research should seek to differentiate between biomedical substitution for prescription pharmaceuticals and psychoactive drug substitution, and to elucidate the mechanisms behind both. [Lucas P, Walsh Z, Crosby K, Callaway R, Belle-Isle L, Kay B, Capler R, Holtzman S. Substituting cannabis for prescription drugs, alcohol, and other substances among medical cannabis patients: The impact of contextual factors. Drug Alcohol Rev 2016;35:326-333].

Keywords: addiction; cannabis; marijuana; substance use; substitution effect.

MeSH terms

  • Adolescent
  • Adult
  • Age Factors
  • Alcohol Drinking / epidemiology*
  • Canada / epidemiology
  • Cross-Sectional Studies
  • Female
  • Harm Reduction
  • Humans
  • Illicit Drugs
  • Male
  • Marijuana Smoking / epidemiology*
  • Medical Marijuana / administration & dosage*
  • Middle Aged
  • Substance-Related Disorders / epidemiology*
  • Surveys and Questionnaires
  • Young Adult


  • Illicit Drugs
  • Medical Marijuana