New Report Shows Increased Risk Of Cannabis Creating False Memories

Scientific Reports has published a new Washington State University study that supports previous findings from other research that shows cannabis can induce false memories.

Via Zoom, Washington State University researchers watched users as they smoked high-potency cannabis flower or vaped concentrates that the participants bought from dispensaries in Washington state. A control group didn’t use cannabis at all. Researchers then gave the subjects a series of cognitive tests. Researchers opted to give volunteers cannabis flower with 20 percent THC or higher to better imitate real-life sessions.

“It’s about external validity,” says Carrie Cuttler, a WSU assistant professor in the psychology department, and lead researcher of the study. “Cannabis research in the U.S. is limited to 6 percent THC flower and rarely any concentrates, since cannabis’ Schedule I status doesn’t give us the access we really need to replicate real-world effects.”

The study didn’t reveal any impact on cannabis user’s performance on decision-making tests. But, memory impairments related to free recall and false memories were discovered. False memory tests were especially revealing. The cannabis users showed increased potential to form false memories. This could create unintended and serious consequences.

“When police interview witnesses after a crime, they ideally want to ensure they are talking to sober people, because intoxicated witnesses using cannabis may be prone to bias and saying something happened when it didn’t,” said Cuttler.

“Overall this showed us that when cannabis is present during a memory test during questioning by the police, cannabis could increase the risk to falsely go along with suggestive but also random questions about an event, increasing the risk that cannabis-intoxicated people may provide false information and thus potentially send an investigation in a wrong direction,” said Dr. Lilian Kloft, a postdoctoral researcher at the University of Maastricht in the Netherlands.

Counter to the oft-presumed idea that high-potency cannabis can be more harmful to our memory than cannabis with medium-grade THC levels Cuttler’s WSU study also points out an intriguing counter: cognitive test scores didn’t vary between the group using 90 percent THC and the one smoking 20 percent THC. 

“There’s been a lot of speculation that these really high-potency cannabis concentrates might magnify detrimental consequences, but there’s been almost zero research on cannabis concentrates which are freely available for people to use,” said Cuttler. “I want to see way more research before we come to any general conclusion, but it is encouraging to see that the concentrates didn’t increase harms.”