Occasional cannabis users may feel stronger effects, study suggests

Men who use cannabis occasionally may experience a stronger high than women with similar habits, according to a small study from UCLA Health.

The research, published in Neuropsychopharmacology, involved 44 healthy adults ages 21 to 55, with equal numbers of men and women. Participants were grouped by how often they used cannabis and took part in three sessions, smoking cannabis with no THC, a lower dose or a higher dose. They were not told which dose they received.

Among occasional users, men said they felt more intoxicated, sedated and impaired than women. They also reported more unpleasant effects, including anxiety, and their heart rates increased significantly after using cannabis containing THC.

Those differences did not appear to be explained by THC levels in the blood. Occasional male and female users had similar peak levels, even though the men reported stronger effects.

Frequent users showed a different pattern: men and women generally responded similarly to active cannabis. People in this group were also more likely than occasional users to enjoy the effects, want to use cannabis again and choose to take more during the study, regardless of sex.

The findings differ from some earlier research suggesting women may be more sensitive to cannabis. The UCLA researchers said past conclusions often relied on animal studies or combined data from separate human trials. In this study, they considered both sex and frequency of cannabis use, and accounted for menstrual cycle timing among women who were not using hormonal birth control.

The researchers said cannabis use history, as well as sex, may influence how someone responds to the drug. Looking at both factors together could help clarify who may be more likely to experience stronger, unpleasant or beneficial effects.

The study had important limitations. It included only 44 people, and some findings about occasional male users came from exploratory analyses that need to be tested in larger studies. The cannabis used contained 4% or 10% THC, lower than the concentration in many products currently sold, which often contain 20% THC or more.

Further research is needed to determine whether men and women develop tolerance differently and whether that affects their risk of cannabis use disorder.