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January 20, 2026
CHARLESTON, S.C. — A common medication used to help people quit smoking cigarettes may offer a new lifeline for those struggling with cannabis addiction, but its effectiveness appears to depend heavily on the patient’s biological sex.
In a randomized clinical trial published January 15 in the journal Addiction, researchers found that varenicline (brand name Chantix) significantly reduced cannabis use among men diagnosed with Cannabis Use Disorder (CUD). However, the results told a strikingly different story for women, who experienced no reduction in use and reported intensified withdrawal symptoms and cravings while taking the medication.
As cannabis legalization spreads across the United States, the findings highlight both a potential new tool for addiction specialists and a widening gap in how men and women respond to pharmacological treatments for substance use.
A Rising Crisis and Limited Tools
The study arrives at a critical juncture for public health. Over the last decade, cannabis use in the U.S. has doubled as more than 30 states have moved toward legalization or decriminalization. While often perceived as a low-risk substance, the clinical reality is more complex: approximately 3 in 10 users develop Cannabis Use Disorder, a condition characterized by an inability to stop using the drug despite it causing health or social problems.
“Current pharmacological treatment options are very limited, and so our ability to help people reduce their cannabis use is also limited,” said lead author Aimee McRae-Clark, a professor at the Medical University of South Carolina (MUSC), in a statement.
The stakes for finding an effective treatment are high. Research published last year indicated that patients hospitalized with CUD face nearly three times the risk of death compared to those without the disorder, leading some experts to label the rise in addiction a “public health crisis.”
The Trial: How the Study Was Conducted
Building on a smaller pilot trial that showed early promise, the MUSC team enrolled 174 participants with CUD. The group, which had an average age of 28, was required to use cannabis at least three times per week.
The participants were split into two groups for a 12-week period:
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The Treatment Group: Received varenicline, starting at 0.5 mg daily and tapering up to a standard 1 mg dose twice daily.
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The Control Group: Received a placebo.
To ensure the results were as accurate as possible, the researchers used a combination of self-reported data and weekly urine tests. They also provided weekly “medical management” sessions—brief clinical check-ins to help participants stay on track with their medication.
The “Sex Effect”: Why Men and Women Responded Differently
When looking at the participants as a whole, the drug appeared to have a negligible effect. However, once researchers separated the data by sex, the “hidden” success of the drug became clear.
The Results for Men
Men taking varenicline saw a marked improvement. Specifically:
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They reported 4.3 fewer weekly cannabis sessions than those on the placebo.
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By the follow-up period, the gap widened to 7.2 fewer sessions per week.
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Men in the treatment group were significantly more likely to provide clean urine samples.
The Results for Women
Conversely, women in the treatment group saw no reduction in use. In fact, women taking varenicline reported:
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Significantly higher withdrawal scores (21.4 vs. 7.0 for the placebo group).
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Increased levels of anxiety and intense cravings.
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Lower medication adherence, suggesting they may have found the drug’s side effects harder to tolerate.
“This is a classic example of why sex-disaggregated data is vital in clinical trials,” says Dr. Elena Rossi, an addiction specialist not involved in the study. “If the researchers hadn’t looked at men and women separately, varenicline might have been dismissed as a failure entirely. Instead, we see it could be a potent tool for roughly half the population.”
Why Varenicline?
Varenicline works by targeting nicotinic acetylcholine receptors in the brain. While primarily used for nicotine addiction, researchers believe these same pathways are involved in the “reward” system of cannabis use.
For men, the drug appears to successfully dampen the urge to use. For women, however, the researchers hypothesize that the medication might inadvertently “prime” the brain’s stress response, making withdrawal symptoms feel more acute and leading to “compensatory use”—using more cannabis to manage the very anxiety the drug may be causing.
Practical Implications and Limitations
For the millions of Americans seeking help for cannabis use, this study offers a nuanced outlook. For men, varenicline represents a potential “off-label” option that physicians might consider, particularly if other interventions have failed.
However, the study had notable limitations:
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Sample Size: Fewer women were enrolled than men, which may have influenced the statistical power of the female-specific results.
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Psychiatric Exclusion: Patients with psychotic disorders or recent history of other substance abuse were excluded, meaning the results might not apply to those with “dual diagnoses.”
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Side Effects: Over 70% of participants reported adverse events, most commonly nausea and vivid “dream disturbances,” which are well-documented side effects of varenicline.
Looking Ahead
The research team at MUSC is already planning follow-up studies. “Our next step is to further explore varenicline for cannabis use disorder, using a larger sample size of women, to better understand this sex difference,” McRae-Clark noted.
For now, the study serves as a reminder that addiction treatment is not one-size-fits-all. While the medical community continues to search for a “gold standard” medication for CUD, this research moves the needle closer to personalized addiction medicine.
References
- https://www.medscape.com/viewarticle/smoking-cessation-drug-could-curb-cannabis-use-2026a10001pg
Medical Disclaimer: This article is for informational purposes only and should not be considered medical advice. Always consult with qualified healthcare professionals before making any health-related decisions or changes to your treatment plan. The information presented here is based on current research and expert opinions, which may evolve as new evidence emerges.
