Cannabis & Long-term Cognitive Implications

A new study looked at over 1,000 young adults, ages 22 to 36, to see how heavy cannabis (marijuana) use affects the brain. Using brain scans, researchers found that people who used a lot of cannabis had less brain activity when trying to remember and use information—something called “working memory.” Working memory helps you with everyday things like driving or having a conversation. The study showed that even people who had stopped using cannabis still had weaker brain activity in these areas. Experts say this could mean that heavy cannabis use might harm your memory and thinking skills, and more research is needed to understand how long the effects last.

“Brain Function Outcomes of Recent and Lifetime Cannabis Use”
(Published in JAMA Network Open, January 2025)
Summary: This study analyzed over 1,000 young adults aged 22 to 36 using brain imaging techniques to assess the impact of cannabis use on brain function. Findings revealed that 63% of heavy lifetime cannabis users and 68% of recent users exhibited reduced brain activity during working memory tasks. Working memory is essential for tasks like following instructions or solving problems. The study underscores the importance of understanding cannabis’s potential cognitive effects. Read about it.

“Year-Long Cannabis Use for Medical Symptoms and Brain Activation During Cognitive Processes”
(Published in JAMA Network Open, September 2024)
Summary: Researchers investigated whether one year of medical cannabis use for symptoms such as anxiety, depression, pain, or insomnia affected brain activation during tasks involving working memory, reward, and inhibitory control. The study involved adults aged 18 to 65 who obtained medical cannabis cards. Results indicated no significant differences in brain activation after one year of use, suggesting that moderate medical cannabis use may not lead to substantial changes in these cognitive domains. ​ ​Read about it.

“Altered Brain Structural and Functional Connectivity in Cannabis Users”
(Published in Scientific Reports, April 2023)
Summary: This study examined 73 cannabis users aged 22 to 36 and compared them with 73 non-users to explore changes in brain connectivity. Using resting-state functional magnetic resonance imaging (rs-fMRI) and diffusion-weighted imaging (DWI), researchers found significant differences in brain network measures, particularly in the insular and frontal opercular cortex and lateral/medial temporal cortex. These regions are associated with functions like decision-making and memory, suggesting that cannabis use may alter brain connectivity in areas critical for cognitive processes. Read about it.