San Francisco Frontiers - UCLA Study Finds Occasional Male Cannabis Users Experience Stronger Effects Than Women

Men who use cannabis occasionally may experience stronger psychoactive effects and higher levels of anxiety than women with similar usage habits, according to new research from UCLA Health. The findings, published in the journal Neuropsychopharmacology, challenge earlier studies that suggested women might be more sensitive to the drug.

The study involved 44 healthy adults aged 21 to 55, evenly divided between men and women. Researchers categorized participants based on their cannabis use frequency—either frequent or occasional—and monitored their responses during three separate sessions. During these sessions, participants smoked cannabis containing no THC, a lower dose of THC, or a higher dose, without knowing which version they were receiving.

Among the occasional users, men reported feeling more intoxicated, sedated, and impaired than women with comparable use histories. The male participants also experienced more unpleasant side effects, including increased anxiety, and showed significant rises in heart rate after using active cannabis. Notably, these differences could not be explained by blood THC levels alone; both groups reached similar peak THC concentrations despite the men reporting stronger effects.

In contrast, frequent users of both genders responded similarly to active cannabis. This group was also more likely than occasional users to report enjoying the effects, wanting to use cannabis again, and choosing to take more during the study, regardless of sex.

Dr. Ziva Cooper, the study’s principal investigator and director of the UCLA Center for Cannabis and Cannabinoids, noted that much of the existing knowledge on sex differences in cannabis effects derived from animal research or human studies that pooled data across different trials. "When we designed a study to look at sex and frequency of use at the same time, and controlled for hormones, the picture changed," Cooper said.

To ensure accuracy, researchers controlled for menstrual cycle timing among female participants who were not using hormonal birth control. Lead author Dr. Stephanie Lake emphasized that both sex and cannabis use history shape how individuals experience the drug. "Studying both together is key to understanding who is most at risk of higher-risk, unpleasant or beneficial experiences from cannabis," she said.

The researchers acknowledged several limitations. The sample size was small, with just 44 participants, and some findings regarding occasional male users were based on exploratory analyses that require confirmation in larger studies. Additionally, the cannabis used in the experiment contained only 4% or 10% THC, which is weaker than many products currently available, where THC levels often exceed 20%.

The study suggests that a person’s history of cannabis use is a critical factor in determining their response to the drug. Researchers stated that larger studies are needed to determine whether men and women develop tolerance differently and how these differences might impact the risk of cannabis use disorder.

F.Garcia--SFF