Adding legal-market cannabis to alcohol impaired immediate word recall—but only in the moment, and only for men. Women showed no additional memory hit from combining the two.
Anyone who combines cannabis and alcohol and wonders about the cognitive effects, and researchers studying sex differences in substance use.
What the researchers found
Sixty adults who regularly used both alcohol and cannabis completed two lab sessions: one with alcohol alone and one with alcohol plus legal-market cannabis. Before and after each session, they took a standard word-recall test.
When cannabis was added to alcohol, participants recalled about one fewer word per trial on immediate recall—a statistically significant but modest effect. This is notable because the study used legal-market cannabis (higher THC than the low-potency research-grade cannabis used in most prior studies), making it more representative of what people actually consume.
The sex difference was striking. Men showed clear additional impairment from cannabis on top of alcohol, while women did not. This wasn't explained by differences in consumption amounts or blood alcohol levels—it appeared to be a genuine biological sex difference in how the combination affects verbal memory.
Short-delay and long-delay recall showed no significant additional impairment from cannabis beyond alcohol alone, suggesting the combination primarily disrupts the encoding phase rather than memory consolidation or retrieval.
Why it matters
Most prior research on combined alcohol and cannabis used low-THC government-supplied cannabis that doesn't reflect real-world products. This is one of the first studies to use legal-market cannabis, and the finding that the combination effect is real but modest—and sex-dependent—adds crucial nuance to public health messaging about mixing substances.
The numbers in context
N = 60 (40% female). Cannabis + Alcohol condition: ~1 fewer word recalled per trial on immediate recall (p < .001). No significant additional impairment on short-delay or long-delay recall. Sex interaction: men showed significant additional impairment, women did not.
How the study worked
Within-subjects design with 60 participants (40% female), all heavy drinkers who regularly use cannabis. Two counterbalanced laboratory sessions: Alcohol Only and Cannabis + Alcohol. Memory assessed using the Rey Auditory Verbal Learning Test (RAVLT) before and after substance use. Legal-market cannabis from a licensed dispensary. Linear mixed-effects models evaluated effects of condition and sex.
Who was studied
N=60 adults aged 21-35, 40% female, heavy drinkers and regular cannabis users from the US.
What this study cannot tell us
Relatively small sample (60 participants). All participants were experienced users of both substances, so results may not apply to naive users. Lab setting may not capture real-world conditions. Only one memory test used (verbal learning); other cognitive domains weren't assessed. Legal-market cannabis varies in potency—results may differ with concentrates or edibles.
How to read the evidence
Randomized within-subjects design using legal-market cannabis, though the sample size is modest and limited to experienced users.
When this study was published
Published in 2025, one of the first co-administration studies using legal-market cannabis rather than low-THC research-grade products.
The bigger picture
This connects to the driving impairment literature (RTHC-00143 found 54.9% of injured drivers tested positive for substances) and the broader question of how combined substance use affects real-world functioning. The sex difference finding also adds to growing evidence that cannabis affects men and women differently—a pattern seen across several domains including anxiety, pain, and cognitive effects.
Replication
Not stated in abstract.
Funding
Not reported in abstract.
Conflicts of interest
Not reported in abstract.
Questions still open
- What drives the sex difference—hormones, body composition, cannabinoid receptor density? Does the combination affect other cognitive domains (attention, executive function) differently? Would the memory impairment be larger in people who don't regularly use cannabis?
Read the original research
Effects of legal-market cannabis and alcohol on verbal learning and memory.
Psychopharmacology
Psychopharmacology is a well-regarded journal that publishes research on the effects of drugs on behavior and mental processes.
Citation
Gowin, Joshua L; Stallsmith, Vanessa; Weldon, Katelyn; Dooley, Gregory; Karoly, Hollis C. (2025). Effects of legal-market cannabis and alcohol on verbal learning and memory.. Psychopharmacology. https://doi.org/10.1007/s00213-025-06882-z
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