A study published in JAMA Network Open examined the potential differences in brain function during cognitive tasks associated with recent cannabis use and lifetime cannabis use.
The research team assessed correlations between recent and lifetime cannabis use and brain function using MRI scans, urine toxicology, and cannabis use data from 1,003 adult participants aged 22 to 36 years. The participants included 470 men [46.9%] and 533 women [53.1%]. Sixty-three participants were Asian (6.3%), 137 were Black (13.7%), and 762 were white (76.0%). For the lifetime history criteria, 88 participants (8.8%) were heavy cannabis users, 179 (17.8%) were moderate users, and 736 (73.4%) were non-users. 8.8% engaged in heavy lifetime cannabis use, while 17.8% were moderate users and 73.4% were non-users.
The participants undertook several tasks administered during functional MRI sessions. These tasks assessed reward, emotion, language, working memory, motor skills, relational assessment, and theory of mind.
The study found that heavy recent and lifetime cannabis use was associated with lower brain activity during a working memory task. 63% and 68% of heavy and recent lifetime cannabis users demonstrated reduced brain activity during one of these tasks, respectively. The brain regions with altered cognitive activity linked to a history of heavy cannabis use included the areas that play a significant role in attention, memory, emotional processing, and decision-making. The team noted the most pronounced lower brain activation in the dorsolateral prefrontal cortex, dorsomedial prefrontal cortex, and anterior insula. The study highlighted an association between brain activity levels during working memory tasks and significant indicators of cognitive function such as intelligence, verbal episodic memory performance, and education. The researchers plan to explore how abstinence or reducing consumption might minimize cannabis’s potentially harmful effects on cognition.
Sources: Healio, JAMA Network Open
