Cannabis use is linked to a significant reduction in alcohol cravings and use, results of a randomized controlled trial showed.

The findings lend support to the trend known as “California sober,” in which individuals use cannabis in place of alcohol to curb drinking. The concept has gained traction in recent years, but evidence to back the approach has been limited.

“To our knowledge, this is the first placebo-controlled randomized trial of cannabis’ acute effects on alcohol craving and consumption in individuals who drink heavily and use cannabis,” the investigators, with first author Jane Metrik, PhD, Center for Alcohol and Addiction Studies at Brown University School of Public Health, Providence, Rhode Island, wrote.

The study was published online on November 19 in The American Journal of Psychiatry 

A Growing Trend

Although the term “California sober” surfaced online as early as 2016, it surged in 2021 after singer Demi Lovato used it in both a song and a documentary. The trend is now “closely linked to the rapid expansion of the THC [tetrahydrocannabinol] beverage market, which caters to individuals seeking alternatives to alcohol,” the investigators noted.

However, evidence on cannabis and alcohol co-use has been mixed, with some observational studies suggesting cannabis may reduce drinking and others linking co-use to heavier alcohol consumption and poorer outcomes, the investigators noted.

Much of this ambiguity reflects a lack of controlled human studies. Despite widespread co-use, no prior trial has established whether cannabis causally increases or decreases alcohol cravings or consumption.

To address this research gap the investigators focused on THC — the primary psychoactive component in cannabis — and evaluated its acute effects on alcohol craving and consumption.

The study included 157 adults who reported heavy drinking and used cannabis at least twice a week. Participants were randomized in a double-blind, crossover design to smoke cannabis cigarettes containing either 7.2% THC, 3.1% THC, or a placebo dose with 0.03% THC. Each participant completed up to three sessions over the 3-day study, one for each dose condition; 138 individuals (65% men; mean age, 26 years) completed at least two sessions.

After smoking the assigned cannabis dose, participants completed a series of neutral and personalized alcohol cue exposures, followed by an alcohol self-administration task in which they could choose to drink or receive money for drinks not consumed.

The primary outcomes included the Alcohol Craving Questionnaire-Short Form, Revised and a single question on alcohol urge. The secondary outcome was the percentage of the total available alcohol participants chose to drink.

‘Risky, Premature’ to Recommend

After any cannabis use, craving for alcohol did not change significantly during alcohol cue exposure. However, the 7.2% THC group did show an immediate reduction in alcohol urge compared with the placebo group (P = .001).

The 7.2% THC group also had a 27% reduction in alcohol consumption relative to placebo (P < .001) over a 2-hour period, while the 3.1% THC group had a 19% reduction (P = .001). The difference in consumption between the two active THC groups was not significant.

Exploratory analyses also showed that the 7.2% THC dose delayed the start of drinking, extending the time to first drink by about 48% compared with placebo (P = .005).

“What we found was consistent with this idea of the substitution effect popularized by the California sober trend,” Metrik said.

However, the researchers cautioned that “it would be premature and potentially risky” to recommend cannabis as a therapeutic substitute for alcohol in patients with alcohol use disorder based on the study’s findings.

“For patients who are already substituting cannabis for alcohol, clinicians should provide guidance on the risks of cannabis use disorder, help monitor cannabis use, and continue recommending evidence-based alcohol treatments,” the researchers concluded.

This study was funded by National Institute on Alcohol Abuse and Alcoholism grant and Research Career Development Awards. One investigator reported being a principal and senior scientist at Beam Diagnostics and having served as a consultant for Clairvoyant Therapeutics. Metrik and the other researchers reported no relevant financial relationships.