A recent study published in JAMA Network Open delves into the impact of both recent and lifetime cannabis use on brain function during cognitive tasks. The study, the largest of its kind ever conducted, analyzed over 1,000 young adults aged 22 to 36 using brain imaging technology. The findings revealed that 63% of heavy lifetime cannabis users showed reduced brain activity during a working memory task, while 68% of recent users exhibited a similar effect.
Working memory is crucial for tasks that involve retaining and utilizing information to perform activities. This cognitive function enables individuals to follow instructions, solve problems, and manipulate information mentally. The decline in brain activity observed in heavy cannabis users was associated with poorer performance on working memory tasks.
Lead author of the study, Joshua Gowin, Ph.D., emphasized the importance of studying the effects of cannabis on human health as its use continues to rise globally. Understanding the potential benefits and risks associated with cannabis can empower individuals to make informed decisions about their usage.
The study classified heavy users as individuals who have used cannabis over 1,000 times in their lifetime, while moderate users have used it 10 to 999 times, and nonusers have used it less than 10 times. The researchers conducted MRI scans on participants and administered seven cognitive tasks to assess various cognitive functions, including working memory, reward, emotion, language, motor skills, relational assessment, and theory of mind.
The study revealed a statistically significant impact of cannabis on brain function during working memory tasks, particularly in heavy users. This effect was less pronounced in other cognitive tasks. The researchers observed reduced brain activity in specific brain regions associated with decision-making, memory, attention, and emotional processing in heavy cannabis users during working memory tasks.
Gowin suggested that abstaining from cannabis use before engaging in cognitive tasks could potentially improve performance. However, abruptly stopping cannabis use may also disrupt cognitive function, especially in heavy users. Further research is needed to explore how cannabis directly affects brain function, the duration of these effects, and the impact on different age groups.
The study, titled “Brain Function Outcomes of Recent and Lifetime Cannabis Use,” was published in JAMA Network Open in 2025. For more information, you can access the full study through the DOI link provided. This research was conducted by the CU Anschutz Medical Campus.
As the scientific community continues to investigate the relationship between cannabis use and brain function, it is essential for individuals to stay informed and make educated decisions about their cannabis consumption habits.
