A new study suggests that cannabis use may weaken brain function and may have an impact, particularly in memory-related tasks.
Researchers found that both recent and long-term cannabis users exhibited reduced brain activity when performing cognitive exercises, raising concerns about its impact on mental performance.
Cannabis and its growing use
Cannabis, also known as marijuana, is one of the most widely used substances worldwide. With increasing legalization and social acceptance, more people are using it for recreational and medicinal purposes.
However, scientists are still studying its long-term effects on the brain. While some research highlights potential medical benefits, growing concerns exist about how frequent use may impact cognitive functions, including memory and decision-making.
Details of the study
The study, conducted at the University of Colorado Anschutz Medical Campus, analyzed brain scans of more than 1,000 adults aged 22 to 36.
Participants were divided into three groups: heavy users (more than 1,000 times in their lifetime), moderate users (10 to 999 times), and nonusers (fewer than 10 times).
Using MRI technology, researchers measured brain activity while participants completed seven cognitive tasks assessing memory, decision-making, emotional responses, language skills, and motor control.
Paper in a JAMA journal of 1003 young adults demonstrates that cannabis use – short term and lifetime – screws with your brain. And not in a good way. And given wide 95% CI, some folk are really screwed. pic.twitter.com/PVaCxyeigv
— Andrew Moore (@AndrewMoorepain) February 3, 2025
The most significant effects were seen in working memory, which is responsible for recalling and using information to complete tasks.
Key findings from the study
The study found that 63% of heavy cannabis users and 68% of recent users displayed reduced brain activity during memory-related tasks. Lower brain activity was linked to difficulty following instructions, solving problems, and retaining information.
“We applied the highest standards to our research, setting rigorous thresholds for statistical significance across all seven cognitive function tests,” said Dr. Joshua Gowin, assistant professor of radiology at the University of Colorado School of Medicine.
He further added, “While some of the other tasks indicated potential cognitive impairment, only the working memory task showed a statistically significant impact.”
🚨 BREAKING NEWS: New Study Reveals Heavy Cannabis Use Linked to Memory Decline 🚨
A groundbreaking study on over 1,000 young adults confirms that heavy cannabis use is significantly associated with weaker working memory and reduced brain activity in key cognitive areas.… pic.twitter.com/eezyzDYQOT
— Quincy Norton (@Bear_Battleborn) January 31, 2025
Brain scans revealed that heavy cannabis use reduced activity in key regions responsible for memory, focus, and decision-making, including the prefrontal cortex and anterior insula. However, the study did not find strong evidence linking cannabis use to impairments in language skills or motor control.
Impact and future research
While avoiding cannabis before cognitive tasks may help improve performance, Gowin cautioned that quitting suddenly could also cause temporary cognitive disruptions, especially for heavy users.
“People need to be aware of their relationship with cannabis since abstaining cold turkey could disrupt their cognition as well. For example, heavy users may need to be more cautious,” Gowin said.
With cannabis use increasing globally, experts emphasize the need for a deeper understanding of its impact on health. Gowin stressed, “As cannabis use continues to grow globally, studying its effects on human health has become increasingly important.”