A new study contains a finding that runs counter to common stereotypes about marijuana and forgetful stoners: smoking cannabis actually seems to improve working memory.
Researchers at the University of Florida acknowledged that their study, which involved rats and was published in the journal Neurobiology of Learning Memory, was unique. Much previous research has concluded that cannabis impairs cognitive performance. But the same time, many of those studies didn’t involve actually inhaling marijuana smoke like this one did.
The team put the 32 rats (split evenly by gender) through a pair of delayed response tasks that involved either finding and pressing a lever a certain amount of times or poking their nose into a feeding trough a certain amount of times—the reward being food pellets, of course. The first few times, the rats were sober; in subsequent experiments, they were exposed to cannabis smoke.
“Cannabis smoke improved working memory accuracy. Placebo smoke did not affect working memory accuracy.”
For male rats, the marijuana didn’t seem to have any effect at all, but for female rats “exposure to cannabis smoke significantly enhanced choice accuracy,” the researchers wrote. That said, baseline performances (prior to exposure) were lower in females compared to males, which “raises the possibility that the enhancing effects in females were due to their relatively worse baseline performance rather than to sex differences in the effects of cannabis per se.”
“The overwhelming majority of research in both animal models and human subjects shows that acute administration of cannabis and cannabinoids induces deficits in tests of cognitive function, including working memory. In contrast, the current experiments show that acute exposure to cannabis smoke enhanced working memory performance in a delayed response task in rats, particularly in females in which baseline levels of task performance were lower than those in males.”