A 2019 study from the University of Colorado at Boulder examined effects on the brain resulting from cannabis use in older adults. Researchers studied magnetic resonance imaging (MRIs) of 28 cannabis users over the age of 60 and gave the participants computerized cognitive tests. They then compared the results of cannabis-using older adults to a non-cannabis-using control group.
Findings, published in Psychiatry Research: Neuroimaging, reflect no significant differences in cortical volume, also known as grey matter, between the two groups. (Grey matter in the brain spans regions involved in speech, memory, emotions, decision-making, and many other functions.) The cannabis-using group also performed equally well on cognitive tests, prompting researchers to conclude that cannabis use in older adults is not associated with cognitive deficits.