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Study Shows Cannabis Disrupts Multiple Memory Systems
Researchers find THC impairs recall, creates false memories, and disrupts source memory.
Mar. 23, 2026 at 7:00pm
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A new study from Washington State University found that cannabis use significantly impairs multiple types of memory, including verbal, visual, false memory, and the ability to recall the sequence, timing, and origin of information. The study examined 120 regular cannabis users, who performed worse on 15 out of 21 memory tests compared to a placebo group, with the biggest effects seen in false memory and source memory.
Why it matters
As cannabis becomes more widely legalized, this research highlights the potential cognitive risks of acute intoxication, especially in situations where accurate recall is essential, such as taking medication, keeping appointments, or determining the reliability of information sources.
The details
The study, published in the Journal of Psychopharmacology, divided participants into three groups: one received a placebo, one consumed 20mg of THC, and one consumed 40mg of THC. Participants then completed a series of memory assessments, including tests of verbal, visual, false memory, and source memory. The cannabis users performed significantly worse than the placebo group on 15 of the 21 tests, with the biggest impairments seen in false memory (where they were more likely to recall words that were never presented) and source memory (where they struggled to identify where previously learned information came from).
- The study was recently published in March 2026.
The players
Carrie Cuttler
An associate professor of psychology at Washington State University and co-author of the study.
Ryan McLaughlin
Co-author of the study and colleague of Carrie Cuttler at Washington State University.
What’s next
The researchers say the study highlights the need for further research on the cognitive effects of cannabis as legalization continues to spread.
The takeaway
This study underscores the potential risks of cannabis use, especially in situations requiring clear memory and reliable information recall. As more states legalize the drug, understanding its cognitive impacts is crucial for consumers to make informed decisions.
