Cannabis use led to persistent cognitive impairment
According to scientists, the compounds in cannabis can continue to affect mental performance for months after use.
Cannabis is the third most popular psychoactive substance in the world after alcohol and nicotine. It contains the chemical compound delta-9-tetrahydrocannabinol, which is responsible for most of the characteristic effects of marijuana. It has been legalised to some extent in several dozen countries, and recently more and more states have joined the list. However, it pays to be clear about the possible consequences of consumption. For example, it is known that regular "pot smoking", despite some therapeutic properties, increases the risk of developing mental disorders like schizophrenia.
The authors of the new review, from the Department of Psychiatry and Addiction Medicine at the Faculty of Medicine of the University of Montreal in Canada, aimed to determine the extent to which cannabis affects cognitive function in adolescents and adults immediately after use and in the long term. The results are published in the journal Addiction.
Researchers conducted a systematic meta-review of studies that assessed people's performance on cognitive tasks: testing executive function, learning and memory, attention, information processing speed, perceptual-motor function and language. In total, ten papers and 43,761 people were included in the sample. The studies analysed ranged from experiments with 65 volunteers to experiments involving thousands.
The authors confirmed that heavy and frequent cannabis use interferes with good decision-making, flexible thinking and self-control. The areas most affected in cannabis users were language memorisation and memory, with the side effect persisting even after intoxication had passed. Young people who were active cannabis users showed residual neurocognitive impairment.
"Our study highlighted several areas of cognitive function impaired by cannabis use - including problems with concentration and difficulties with memory and learning - that can severely affect daily life," said one of the review's authors, Alexandre Dumé, a professor of psychiatry at the University of Montreal. - Consequently, cannabis use at a young age can lead to lower educational attainment and, in adults, to poor performance and dangerous driving. These effects will be more severe in avid cannabis users."