Alcohol and cannabis co-use is increasingly prevalent in countries where marijuana is legal. But does one impact on the consumption of the other?
There have been conflicting results from studies examining this — some indicated cannabis co-use is associated with reductions in alcohol consumption, others an increase or no change at all.
Colorado State University and University of Colorado researchers set out to draw their own conclusions through investigating the effects of legal-market cannabis on alcohol consumption in a laboratory setting; claimed to be the first study of its type.
61 individuals completed two laboratory sessions where they were given an alcohol “priming” drink on its own or after self-administering cannabis. Participants could then self-administer up to 4 additional drinks. The researchers found cannabis self-administration was associated with a significant reduction in number of subsequent drinks. Additionally, those who drank less after using cannabis (23 participants) had reductions in craving after using cannabis and alcohol compared to alcohol alone.
No significant group differences in blood-THC concentration post-cannabis use were observed.
The researchers state:
“Results indicate that for some individuals who drink heavily, cannabis may serve as a substitute for alcohol, and craving reduction is a potential mechanism through which this could occur.”
Among the eligibility criteria for participants.
- Between the ages of 21–60.
- Heavy drinking for at least 3 months, which was defined as > 4 drinks on any day or more than 14 drinks per week for men; more than 3 drinks on any day or more than 7 drinks per week for women.
- Regular cannabis flower use.
The study has been published in the journal Drug and Alcohol Dependence. The research was supported by the National Institutes on Health’s National Institute of Alcohol Abuse and Alcoholism.
The researchers have recommended future studies delve into additional individual and contextual factors that could act as predictors as to whether cannabis serves as a substitute for alcohol.
A Canadian study published in 2020 involving many more participants found 44% reported decreases in alcohol usage frequency over 30 days and 34% had decreased the number of standard drinks consumed per week. 8% reported no alcohol use at all in the 30 days prior to the associated survey.
