Smoking cannabis can help people regulate their drinking and is associated with an acute reduction in alcohol use, according to a new study investigating the effectiveness of California sober, an increasingly popular harm reduction approach.
The randomised, double-blind, controlled trial, published in The American Journal of Psychiatry, examined 157 participants who self-reported heavy cannabis and alcohol use. Researchers from Brown University in the United States found that after smoking joints containing either 7.2% or 3.1% THC (tetrahydrocannabinol), participants’ alcohol consumption decreased significantly compared to those who received a placebo.
California sober is a philosophy in which followers abstain from drinking alcohol and taking ‘hard’ drugs, such as cocaine and amphetamines, but continue to use cannabis, and sometimes psychedelics. The approach is viewed as a form of harm reduction because cannabis and psychedelics are considered by many to be less harmful than other drugs.
Participants aged 21 to 44 were required to have used cannabis at least twice weekly for the previous six months and engaged in heavy episodic drinking (five or more drinks for men, four or more for women) at least once monthly over the past year. All participants tested positive for THC at baseline and were familiar with smoking cannabis.
During the study, participants took part in three experimental sessions in which they smoked a joint that contained either 7.2% THC, 3.1% THC, or 0.03% THC (the placebo). All three joints contained less than 0.22% CBD.
Participants were instructed to abstain from cannabis and alcohol for 15 hours before their sessions, and not to consume caffeine for three hours prior. They underwent health assessments before and after the sessions, and completed other evaluations to assess alcohol cue-reactivity and their desire to drink.
The participants also completed an ‘Alcohol Choice Task’ after they smoked their joint, in which they were given the choice to drink eight small alcoholic drinks in a simulated bar. They were given a monetary reward for every drink not consumed.
The results showed that after participants had smoked the joints containing 7.2% and 3.1% THC, their alcohol consumption decreased significantly and the time it took them to initiate drinking in the bar setting increased, when compared to the placebo. The effects did not change much between the two doses of THC.
The 3.1% THC dose reduced consumption by 19% compared to placebo (29.52% versus 36.25%), whilst the 7.2% THC dose decreased consumption by 27% (26.61% versus 36.25%). The higher dose also increased the time before participants began drinking by 48%, from an average of 22.5 minutes to 33.4 minutes.
“The findings suggest that smoked cannabis reduces alcohol consumption and, conversely, acute cannabis deprivation (i.e., in the placebo condition) may lead to compensatory increases in alcohol intake.”
Interestingly, cannabis did not consistently affect alcohol craving as measured by the Alcohol Craving Questionnaire, though the 7.2% dose did significantly suppress the urge to drink immediately after smoking.
The findings coincide with those of a previous study, which found cannabis to help young drinkers reduce their alcohol consumption.
“Those who drank less after cannabis reported greater decreases in alcohol craving,” the researchers noted. They also found that “self-administering cannabis before alcohol significantly reduced alcohol consumption compared to when alcohol was offered without cannabis.”
Cannabis use is traditionally linked to alcohol use disorder, especially in people with cannabis use disorder. Using both substances together is related to negative outcomes, including heavy drinking, risky driving, poor psychological and physiological health outcomes, and poor alcohol use disorder treatment outcomes.
While researchers from the current study are confident that cannabis use can help decrease alcohol use in heavy drinkers, they did, however, call for more research to be conducted to assess the potential harm it may cause, and with cannabis containing differing levels of cannabinoids.
The study found that smoked cannabis induced acute increases in subjective intoxication, cardiovascular effects, and blood THC concentrations whilst reducing alcohol consumption. However, participants still consumed alcohol after smoking cannabis with THC, although they drank less than when they received the placebo.
“These data provide preliminary evidence that cannabis may reduce alcohol consumption under some conditions, but whether this would result in reductions in harms associated with simultaneous use is unknown,” the researchers wrote.
They added that controlled human studies can help address the lack of empirical data on alcohol consumption in relation to cannabinoid use. Clinical research is needed on the effects of various cannabinoids and endocannabinoid targets used simultaneously with alcohol versus sequentially to evaluate clinically relevant alcohol outcomes.
“While there is growing recognition of the therapeutic potential of cannabinoids, it would be premature and potentially risky at this time to recommend cannabis as a therapeutic substitute for alcohol or as a harm-reduction strategy for AUD.”
