A recent study published in JAMA Network Open investigates the effects of both recent and long-term cannabis use on brain function during cognitive tasks, focusing mainly on over 1,000 young adults aged between 22 and 36. Utilizing advanced brain imaging technology, the study meticulously recorded participants’ brain activity as they engaged in various cognitive challenges. The results showed a significant reduction in brain activity in 63% of heavy lifetime cannabis users and 68% of recent users during tasks that assess working memory. This decline in cerebral function was directly linked to poorer performance in working memory tasks, which are crucial for tasks such as following instructions or solving problems in one’s head.
The increasing global prevalence of cannabis use underscores the importance of such studies. According to Joshua Gowin, PhD, the lead author and an assistant professor of radiology at the University of Colorado School of Medicine, understanding the effects of cannabis is essential for enabling people to make informed decisions regarding its use. By comprehensively examining the impact of cannabis on various cognitive functions, the study aims to provide a balanced perspective on both the potential benefits and risks associated with cannabis consumption.
Participants in the study were categorized based on their cannabis usage: heavy users (over 1,000 times), moderate users (10 to 999 times), and non-users (less than 10 times). The researchers assessed the neural responses of these individuals using magnetic resonance imaging (MRI). At the same time, they performed seven cognitive tasks designed to test functions such as working memory, emotional response, and motor skills. The study found that cannabis has a statistically significant effect on brain function during working memory tasks, suggesting the observed impacts are unlikely to be coincidental. This effect was prevalent in recent and longtime users, although it was less significant in other cognitive tasks.
Dr. Gowin emphasized the rigorous standards employed in their research, mainly using false discovery rate (FDR) correction to minimize the risk of false positives across all seven cognitive tests. While some tasks indicated potential cognitive impairments, only the working memory tasks showed a statistically significant impact. This points to the need for a nuanced understanding of how different mental functions are affected by cannabis use.
Significantly, the study highlighted that heavy cannabis use tends to suppress activity in critical brain regions such as the dorsolateral prefrontal cortex, dorsomedial prefrontal cortex, and anterior insula, which are involved in key cognitive processes, including decision-making, memory, attention, and emotional regulation. However, Dr Gowin also noted that abstaining from cannabis before performing cognitive tasks could improve performance, advising that users need to be aware of their consumption patterns as sudden cessation could also disrupt cognitive function.
Dr Gowin concluded by advocating for further research to explore the direct impact of cannabis on brain function, the duration of these effects, and their implications across different age groups. He stressed the importance of extensive, long-term studies to deepen our understanding of the long-term effects of cannabis on cognitive health, thus paving the way for more informed public health policies and individual choices regarding cannabis use.
More information: Joshua Gowin et al, Brain Function Outcomes of Recent and Lifetime Cannabis Use, JAMA Network Open. DOI: 10.1001/jamanetworkopen.2024.57069
Journal information: JAMA Network Open Provided by University of Colorado Anschutz Medical Campus
