Occasional male marijuana users feel more high, more sedated and more impaired than women with the same usage habits, according to a new study out of UCLA Health.
The research, published in the journal Neuropsychopharmacology, tracked 44 healthy adults ages 21 to 55, split evenly between men and women. Participants were further divided by how often they used cannabis: occasionally or frequently.
Each person sat through three sessions, smoking cannabis with no THC, a lower THC dose, or a higher THC dose, without knowing which one they’d gotten.
Among occasional users, men reported stronger highs, more sedation, more impairment and more unpleasant side effects including anxiety than women with similar habits. Their heart rates also climbed significantly after using active cannabis. This happened despite blood THC levels peaking at roughly the same point for both sexes in that group — meaning THC concentration alone doesn’t explain the gap.
Frequent users told a different story. Men and women who used cannabis often responded to it in largely the same way, and frequent users overall were more likely than occasional users to say they liked the drug’s effects, wanted more of it, and actually took more during the study.
Pushback on Prior Assumptions
The results cut against earlier research suggesting women are more sensitive to cannabis than men.
“Much of what we thought we knew about sex differences in cannabis effects came from animal research and from human studies that pooled data from different trials,” said Dr. Ziva Cooper, the study’s principal investigator and director of the UCLA Center for Cannabis and Cannabinoids. “When we designed a study to look at sex and frequency of use at the same time, and controlled for hormones, the picture changed.”
Researchers controlled for menstrual cycle timing among female participants, none of whom were on hormonal birth control.
“Sex and cannabis use history can both shape how someone experiences the effects of cannabis,” said lead author Dr. Stephanie Lake, a researcher at the UCLA Center for Cannabis and Cannabinoids. “Studying both together is key to understanding who is most at risk of higher-risk, unpleasant or beneficial experiences from cannabis.”
Limits of the Study
The researchers flagged real caveats. The sample was small — just 44 people — and several findings on occasional male users came from exploratory analysis, meaning they’ll need confirmation in larger trials.
The cannabis used in the study contained 4% or 10% THC, far weaker than what’s commonly sold today, where THC levels of 20% or higher are standard. Researchers say larger studies are needed to determine whether men and women build tolerance differently, and how that might affect risk of developing cannabis use disorder.
