A systematic review of 29 studies found limited evidence that sex influences the acute cognitive effects of cannabis or THC in humans. Only 6 of 29 articles (20.7%), representing 8 of 216 cognitive outcomes (3.7%), reported sex differences. All six studies found greater cognitive impairment in female participants for at least one measure; one study also found greater effects in male participants, and one found divergent effects between sexes. No consistent patterns emerged by cognitive domain, route of administration, or dosing paradigm. Methodological heterogeneity across studies prevents firm conclusions, and future research should examine hormonal modulation of cannabinoid effects.
A genetic variant of ABCB1, which encodes a protein that pumps substances out of cells, may influence how the body processes THC from smoked cannabis. In 48 young adults who used cannabis 1–4 days per week, those carrying a C allele at the rs2235048 polymorphism had higher blood levels of THC metabolites after smoking a single cannabis cigarette than those with the TT genotype. C-allele carriers also reported using cannabis more frequently each week and greater drug liking. No other subjective drug effects differed between groups. The findings are preliminary and suggest that ABCB1 could affect cannabis-related traits and risk for cannabis use disorder, but larger studies are needed.