People Drink ‘Significantly Less Alcohol’ After Smoking Marijuana, Federally Funded Study Shows

Smoking marijuana is associated with “significantly” reduced rates of
alcohol consumption, according to a new federally funded study that
involved adults smoking joints in a makeshift bar.

Researchers at Brown University investigated the science behind the trend
that’s come to be known as “California sober,” referring to people who
abstain from or limit the use of alcohol and most other drugs while still
consuming cannabis.

According to the study, published on Wednesday in the American Journal of
Psychiatry, smoking marijuana could actually be helping people moderate
their drinking. That’s based on the findings of the researchers’
experiment, which involved 157 adults who reported heavy alcohol and
cannabis use at least twice weekly and who were tasked with smoking joints
in fabricated bar setting.

“What we found was consistent with this idea of the substitution effect
popularized by the California sober trend,” Jane Metrik, a human behavior
and psychiatry professor at Brown University, said in a press release.
“Instead of seeing cannabis increase craving and drinking, we saw the
opposite. Cannabis reduced the urge for alcohol in the moment, lowered how
much alcohol people consumed over a two-hour period and even delayed when
they started drinking once the alcohol was available.”

The participants were given marijuana joints containing either 7.2 percent
THC, 3.1 percent THC or 0.03 percent THC (the placebo). After smoking the
cannabis, they were then exposed to “neutral and personalized alcohol cues
and an alcohol choice task for alcohol self-administration.”

An alcohol cue assessment that the participants completed showed that those
who smoked the two higher THC concentration joints “consumed significantly
less alcohol,” with an average 27 percent reduction in drinking for those
who received the 7.2 percent THC joint and 19 percent for the 3.1 percent
THC cohort.

Researchers said that, for participants who smoked joints with 7.2 percent
THC, that also “reduced alcohol urge immediately.”

“Following overnight cannabis abstinence, smoking cannabis acutely
decreased alcohol consumption compared to placebo,” it found. “Further
controlled research on a variety of cannabinoids is needed to inform
clinical alcohol treatment guidelines.”

"California sober"—ditching alcohol in favor of #cannabis—is gaining
popularity.🍸

Follow the link for the findings of the first ever, randomized,
placebo-controlled trial to test whether smoking cannabis directly changes
alcohol consumption⤵️ https://t.co/NnIB5Qwvxq pic.twitter.com/8FEvN8Nxcn

— Brown University School of Public Health (@Brown_SPH) November 19, 2025

The study authors said this represents the first placebo-controlled
randomized trial that specifically looks at the acute effects of marijuana
use on alcohol cravings and consumption for heavy users.

“Extending the latest scientific evidence, we found that smoked cannabis
with 3.1 percent and 7.2 percent THC doses acutely decreased alcohol
consumption and increased latency to drink under controlled laboratory
conditions, relative to placebo,” the study authors said, adding that the
effects of the non-placebo joints “were not statistically different from
each other.”

“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,” the study says.

“In concert with experimental investigations and studies demonstrating
substitution effects, our findings support the substitution model of
cannabis and alcohol co-use. In the absence of consistent effects of
cannabis on alcohol craving, a possible mechanism whereby cannabis reduces
alcohol consumption may be through satiation, such that participants may
have reached their preferred experiential intoxication on one drug, which
may have lowered desire for the other substance. The findings also suggest
that individuals titrate their alcohol consumption based on their current
state of intoxication to reach a desired level of overall intoxication.”

One theory the researchers put forward as to why cannabis use seems to
inhibit alcohol consumption and cravings is that most participants were
daily marijuana users. Because cannabinoids downregulate certain receptors
in the endocannabinoid system, that may “functionally impair alcohol reward
processing and alcohol motivation.”

The researchers also noted that, while their study involved cannabis flower
with relatively lower concentrations of THC compared to what’s available in
state medical and adult-use markets, the findings are still relevant,
indicating that alcohol consumption and cravings could also be reduced for
someone taking relatively fewer hits of high-THC varieties.

Further, the study notes that the cannabinoid concentration of marijuana
flower and its formulation “could influence the direction of effect on
alcohol-related outcomes.”

While this experiment focused on THC, prior research on animal models has
indicated that non-intoxicating CBD is also associated with reduced alcohol
use—and observational studies suggest that the use of CBD is associated
with lower alcohol consumption compared to THC. Therefore, “smoking
cannabis flower containing CBD could lead to even greater reductions in
alcohol use.”

“The study findings demonstrate that smoked cannabis induced acute
increases in subjective intoxication, affect, arousal, cardiovascular
effects, blood THC concentrations, and acutely reduced alcohol consumption
without a consistent effect on alcohol craving,” it says. “Notably,
participants still consumed alcohol after smoking cannabis with THC,
although they drank less than when they were not acutely intoxicated with
THC. 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.”

“Controlled human studies like this one can help address the dearth of
empirical data on alcohol consumption in relation to cannabinoid use and
shed light on the inconsistent findings from epidemiological studies.
Clinical research is needed on the effects of a variety of 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. 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.”

Metrik said that what the research team found is that “cannabis reduces the
urge in the moment,” but the long-term effect warrants further
investigation.

“Our job as researchers is to continue to answer these questions,” she
said. “We can’t tell anyone yet, ‘you should use cannabis as a substitute
for problematic or heavy drinking.’”

The study received funding from the National Institute on Alcohol Abuse and
Alcoholism (NIAAA) under the National Institutes of Health (NIH). Cannabis
plant material used in the study was provided by the National Institute on
Drug Abuse (NIDA) through its drug supply program.

While the researchers say they’re not willing to say the study definitively
proves marijuana should be considered as an alcohol alternative or
treatment for alcoholism, the findings are consistent with a growing body
of research indicating that cannabis does have that potential—and more
people are opting for the plant over alcohol.

A study published earlier this month, for example, found that adults who
drink cannabis-infused beverages has found more evidence of a “substitution
effect,” with a significant majority of participants reporting reduced
alcohol use after incorporating cannabinoid drinks into their routines.

A survey released last month also showed that four in five adults who drink
cannabis-infused beverages say they’ve reduced their alcohol intake—and
more than a fifth have quit drinking alcohol altogether.

Recent polling additionally shows that younger Americans are increasingly
using cannabis-infused beverages as a substitute for alcohol—with one in
three millennials and Gen Z workers choosing THC drinks over booze for
after-work activities like happy hours.

Another poll released last month found that a majority of Americans believe
marijuana represents a “healthier option” than alcohol—and most also expect
cannabis to be legal in all 50 states within the next five years.

The post People Drink ‘Significantly Less Alcohol’ After Smoking Marijuana,
Federally Funded Study Shows appeared first on Marijuana Moment.