Scientists are investigating whether cannabis use can lead to reduced alcohol consumption, a phenomenon sometimes referred to as "California sober." Recent research provides data suggesting that cannabis may decrease alcohol intake, at least in the short term. These findings, published in the American Journal of Psychiatry, contribute to the ongoing discussion about substance interaction and public health.
Study Design and Findings
Jane Metrik, a professor of behavioral and social science at Brown University, led a study designed to replicate real-life substance use conditions within a controlled laboratory environment. The team constructed a lab resembling a bar, providing participants with their preferred alcoholic beverages. The experiment involved three sessions:
- High-potency cannabis: Participants smoked a joint with elevated levels of THC.
- Lower-potency cannabis: Participants used a strain with reduced potency.
- Placebo: Participants received a placebo containing a trace amount of THC insufficient to induce psychoactive effects.
After cannabis administration, participants spent two hours in the simulated bar, with access to up to eight mini-drinks. The results indicated that participants who used higher potency cannabis consumed 27% less alcohol, while those using lower potency cannabis consumed approximately 19% less, compared to the placebo group. Cannabis users also exhibited a delay in initiating alcohol consumption. Metrik suggested that these findings indicate a potential therapeutic role for cannabinoids in alcohol use disorder.
Previous observational studies and animal research have also indicated that cannabis might reduce alcohol cravings and consumption, though controlled experimental data has been less extensive. These new findings align with earlier research conducted in Colorado, where participants who used cannabis at home and then visited a mobile lab consumed about 25% less alcohol, with reported reductions in cravings.
Limitations and Considerations
Both studies acknowledge limitations, particularly regarding the generalizability of lab-based behavior to uncontrolled real-world social settings. Hollis Karoly, who led the Colorado study, noted that the reduction in alcohol consumption was not universal among participants; a minority consumed more alcohol. This highlights the significance of individual differences.
The participant demographics in the Brown study, where most met criteria for cannabis use disorder and a significant portion for alcohol use disorder, may influence the interpretation of primary substance preference. Rajita Sinha, a professor of psychiatry at Yale University, suggested that while cannabis might offer a potential treatment for problematic drinking, it could also lead to increased cannabis use, which warrants consideration given that frequent cannabis use can lead to dependence.
Researchers involved in this work recognize the complexities of this area. While cannabis is associated with different risk profiles compared to alcohol—a leading cause of preventable death in the U.S.—it is not without associated risks. Despite increasing cannabis popularity, research on its effects has lagged. Studies have shown cannabis can impair cognition and memory, trigger a gastrointestinal syndrome (nausea/vomiting), increase the risk of psychosis and other psychiatric illnesses, and impact relationships and social functioning.
The current studies do not provide data on the long-term comparative harms of alcohol versus cannabis. Researchers emphasize the need for further study to determine which substance may be less harmful for individuals over time, to avoid simply substituting one problem for another. The observed lack of clear clinical guidance for individuals using cannabis to address alcohol problems underscores the need for additional research and clearer messaging.