Weed might be changing your memories.
A new study from Washington State University found that relative to placebo, cannabis made participants more susceptible to false memories. The study also found that participants who consumed THC struggled with everyday tasks, like remembering to do something later.
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The study also found that there was no significant difference between people who had 20 milligrams of THC and those who had 40 milligrams, indicating that even moderate doses may cause disruptions to people’s memory perception.
Published in the Journal of Psychopharmacology, this study was the first to look at how cannabis affects most memory systems, rather than selectively focusing on one or two. The findings suggest that cannabis may impact how people remember events.
Through a randomized, double-blind, placebo-controlled study, participants were randomly assigned to vaporize placebo cannabis with zero THC, 20 milligrams of THC, or 40 milligrams of THC. Then, the participants completed different tests to examine various forms of memory, including verbal, visuospatial, prospective, source, false memory, episodic content, and temporal order memory.
Overall, participants who had any THC performed significantly worse than the placebo group on most measures.
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The strongest effect was on false memory and source memory, which are systems that help people recall information and identify its source. For example, participants who consumed cannabis were more likely to remember hearing words that had never been presented.
However, not all of the findings were definitive. For example, cannabis did not have any significant impacts on episodic content memory, or the memory of personally experienced events, indicating that more research is needed to determine why that is.
While the study indicates that cannabis use may have effects on memory, more research is needed before firm conclusions can be drawn.