A Washington State University research team observed brain activity to map out which aspects of memory are impacted by cannabis use. The study showed that people who consumed tetrahydrocannabidiol (THC) struggled more with everyday tasks. They were also more likely to recall words that were never presented. The findings, published in the Journal of Psychopharmacology, suggest cannabis can impair executive function, which is critical to remembering conversations and appointments.
The research team recruited 120 regular cannabis users. The researchers randomly assigned participants to vaporize a placebo cannabis, 20 milligrams of THC, or 40 milligrams of THC. After consuming the cannabis, the participants completed a battery of tests measuring source, false, episodic content, visuospatial memory (immediate, delayed, short-term, working), verbal, prospective, and temporal order memory.
The participants who consumed cannabis performed significantly worse than the placebo group on most measures. Data analysis revealed significant differences appearing in 15 of the 21 measures, and the strongest impacts appeared in false memory and source memory (systems that facilitate accurate recall information and identification of the source). In one test, the research team presented participants with lists of related words, but not the key word that tied them together. They found that the participants who had consumed cannabis were more likely to remember both related and unrelated words, even though these words were not presented to the participants.
The study also offered insights into how the frequency and amount of cannabis consumed influence memory. Data analysis found no meaningful differences between participants who consumed moderate dose (20 milligrams of THC) and those who consumed high dose cannabis (40 milligrams of THC). Data analysis suggested that even moderate doses may result in substantial cognitive disruptions. The researchers noted that cannabis users had more difficulty remembering the source of information they had learned earlier.
Sources: Eureka News Alert, Journal of Psychopharmacology, Washington State University Insider
