Could Cannabis be a Treatment for Alcohol Use Disorder?

Unlike tobacco and heroin, there is currently no agonist therapy for alcohol. Chick and Nutt recently defined 7 criteria for alcohol “substitution therapy,”* and, in a literature review, Subbaraman assessed whether cannabis could satisfy those criteria:

1. Reduction of alcohol-related harms: Some evidence suggests that cannabis could reduce alcohol use and related harms.
2. Free of harms, or less harmful than alcohol: Available evidence points to cannabis as being safer than alcohol; however, cannabis is not free of harms.
3. “Misuse” should be less than that of alcohol: Epidemiological studies show a lower rate of dependence for cannabis compared with alcohol; however, there is an increased likelihood of cannabis dependence among people with alcohol use disorders.
4. Adequate as a “substitution” for alcohol and not used along with it: Studies showing both “substitution” and use of cannabis as a complement were identified.
5. Safer in overdose than alcohol: The safety ratio for cannabis is over 10 times greater than that of alcohol.
6. Not potentiate the effects of alcohol: Some studies conclude that cannabis potentiates the effects of alcohol while others do not.
7. Significant health economic benefits: There is some evidence at the aggregate level that cannabis may have health economic benefits, but no studies have compared individual health economics outcomes.

In sum, cannabis appears to be less harmful than alcohol and is safer in overdose. Evidence was mixed for the other criteria.

Comments:

Almost all of the evidence to support these findings comes from retrospective studies, and the risk of selection bias is high. Furthermore, most did not focus on people with alcohol use disorders. Further investigation into subsequent harms, problems, and economic consequences of cannabis use is necessary, but the current status of cannabis makes any systematic study unlikely. Nonetheless, there is insufficient evidence to support any recommendation for cannabis as a treatment for or even as a harm reduction strategy for people with an alcohol use disorder, especially in light of its known adverse health effects (see also: Is Marijuana Use Safe? NIDA’s Director Addresses Questions of Adverse Health Effects).

Nicolas Bertholet, MD, MSc

Reference:

Schwartz RP, Gryczynski J,
Chick J, Nutt DJ. Substitution therapy for alcoholism: time for a reappraisal? J Psychopharmacol. 2012;26(2):205-12.
Subbaraman MS. Can cannabis be considered a substitute medication for alcohol? Alcohol Alcohol. 2014;49(3):292–298.