New Study Explores the Effects of Cannabis Use in Cognitive Function

Researchers at the Université de Montréal have recently published a meta-analysis in the journal Addiction, in which they explored current research studies exploring cannabis use and its effects on cognitive function. 

The study included a collection of 10 cannabis meta-analyses, with a total of 43,761 participants, with the aim to learn what these studies revealed about cannabis intoxication and cognitive function.

The review found that cannabis intoxication leads to small to moderate cognitive impairment, depending on the type of cognition, mainly on verbal learning and memory, as well as executive function. They also found that these detrimental effects persist beyond acute intake. 

Of the 10 meta-analyses, 7 explored executive function, 5 memory and learning, 5 processing speed, 4 complex attention, 2 perceptual and motor function, and 2 language. 

Dr. Alexandre Dumais, review’s senior author, told Medical News Today in an interview: 

“Research has revealed that THC [the active ingredient in cannabis] is a fat-soluble compound that may be stored in body fat and, thus, gradually released into the bloodstream for months. Some literature has suggested that effects may persist for at least 1 week when cannabis use is chronic — [and] definitions of chronic use varied between individual studies — though these deficits are often resolved with long abstinence periods,” he said, adding that “long” might refer to 25 days without cannabis use, for example.

“These neurotoxic effects last,” Dr. Dumais explained, “although cannabis users reduce their intake or quit altogether. While some longitudinal studies suggest that cognitive deficits resolve following abstinence (e.g., within the last 12 months), other studies have confirmed that cannabis use frequency led to subsequent long-term cognitive decline, regardless of prolonged cannabis intake. Currently, more research is needed on the matter.”

Most of the studies evaluated have cross-sectional data with evidence that can be of low-to-moderate quality, but this doesn’t rule their conclusions to be invalid. Larger and more controlled studies are needed to draw better conclusions, but the information that we currently have points to a negative cognitive effect with chronic cannabis use.


Robby Berman (2022, Jan 25). Review explores the effects of cannabis use on 6 areas of cognitive function. Medical News Today. Retrieved from:

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