Medical Cannabis Patients Show Sustained Improvements in Cognitive Performance

Belmont, MA: The use of cannabis products, particularly CBD-dominant products, is associated with sustained improvements in cognitive performance, according to longitudinal data published in the Journal of the International Neuropsychological Society

A team of Harvard investigators assessed executive function in a cohort of medical cannabis patients prior to their use of marijuana and then again at three months, six months, and at twelve months. Patients enrolled in the study possessed little-to-no prior experience with cannabis. 

Researchers reported that subjects showed improved cognitive performance within three months of treatment and that these improvements were sustained throughout the 12-month trial period. Improvements in executive function were correlated with clinical improvements in patients’ mood, anxiety, and sleep. The use of CBD-dominant products was most closely associated with participants’ changes in mood and anxiety. 

Authors concluded: “In a 12-month longitudinal, observational study, patients using MC [medical cannabis] for various medical conditions exhibited improved executive function and stable verbal learning and memory within the context of improvements on measures of mood, anxiety, and sleep relative to baseline. [I]mprovement of clinical state over time was significantly associated with increased CBD exposure. … Future investigations examining the impact of individual cannabinoids and age of onset of use are warranted to clarify the implications of MC use. Ultimately, for MC patients, it is imperative to understand the relationship between these variables in order to maximize the therapeutic potential of cannabis while minimizing potential risk and harms.”

A 2020 study published in the journal AIDS Care also reported that HIV patients with a history of cannabis use exhibited better neurocognitive performance than similarly matched patients with no history of consumption. 

Full text of the study, “An observational, longitudinal study of cognition in medical cannabis patients over the course of 12-months of treatment: Preliminary results,” appears in the Journal of the International Neuropsychological Society.