Will Smoking Too Much Weed Damage Your Memory?

A new study conducted by JAMA Network Open discovered that heavy marijuana users are causing damage to their brain’s working memory.

What quantifies a heavy user? The study consisted of 1,003 adults between 22-36 who used cannabis 1,000 or more times in their lifetime. I can’t imagine these people were logging every time they smoked before this research project. But you figure if they asked someone how often they smoke and they responded once a day, then anyone who has been doing so for three or more years probably has hit that threshold.

The report found that 63% of the participants showed reduced brain activity. The study didn’t find any link with long-term memories, but rather what they classify as working memory (such as performing activities).

This included various tests such as remembering instructions and seeing how the individual would follow the verbal commands. These tests were done so while receiving an MRI to see what was going on inside their head.

Is Heavy Marijuana Use Bad for Your Memory?

Joshua Godwin, PhD, is an assistant professor of radiology at the University of Colorado School of Medicine and was the lead on this study. He told Verywell Health that there is still a lot of research needed to be done to determine the long-lasting effects of heavy cannabis use.

The discourse on marijuana has been very active, to say the least. Other studies that have been spotlighted over recent years have linked daily cannabis use to a higher risk of heart failure. Then there are plenty of other reports that promote the benefits of using the substance to lower blood pressure, reduce inflammation, and treat anxiety.

More and more studies like this will certainly be conducted over the next decade as marijuana use continues to rise. As of February 2025, 24 states have legalized recreational marijuana and 40 have instituted medicinal use.