Heavy Cannabis Use May Impair Brain Function, Study Finds
A large study from the University of Colorado found heavy cannabis use is linked to reduced brain activity. Lead researcher Joshua Gowin and neurosurgeon Paul Saphier discuss the impact on health.
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As cannabis becomes legal in more states, new research highlights potential risks associated with excessive use.
A study by the University of Colorado Anschutz Medical Campus, published in JAMA Open Network, examined the effects of cannabis on brain function in 1,000 young adults aged 22 to 36. Researchers used brain imaging technology to measure neural responses during cognitive tasks, particularly working memory—the ability to retain and use information for problem-solving.
Key Findings
- 63% of heavy lifetime cannabis users showed reduced brain activity while performing a working memory task.
- 68% of recent cannabis users exhibited similar effects.
- Cannabis use had a statistically significant impact on working memory but was less pronounced in other cognitive tasks.
- Brain regions responsible for decision-making, memory, attention, and emotional processing showed reduced activity in heavy users.
Expert Insights
Lead author Joshua Gowin, PhD, an assistant professor of radiology at the University of Colorado School of Medicine, emphasized the importance of continued research.
"As cannabis use expands globally, understanding both its benefits and risks allows people to make informed decisions," he stated.
He also noted that avoiding cannabis before cognitive tasks could enhance performance but warned that sudden abstinence might also temporarily disrupt cognition in heavy users.
Neurosurgeon Dr. Paul Saphier, who was not involved in the study, acknowledged the findings but suggested a larger sample size of heavy users is needed for more definitive conclusions.
"Heavy cannabis use over time may impair cognitive and memory tasks," he said. "This supports the common principle of 'everything in moderation,' except for clearly harmful habits."
Looking Ahead
The study raises questions about the long-term impact of cannabis on brain function across different age groups. Researchers call for larger, long-term studies to better understand how cannabis affects the brain and whether these changes are reversible.
