Study Reveals The Dark Side Of Daily Marijuana Smoking: How It Affects Decision-Making And Concentration

This article was originally published in January 2022.

What are, if any, the negative effects of regular marijuana consumption?

Well, according to a comprehensive review published Wednesday in the journal Addiction, cannabis use can lead to small or to moderate acute cognitive impairments that can persist after the period of intoxication, reported MedicalXpress.

The study was conducted by the research center of the Institute Universitiaire En Santé Mentale De Montréal in Canada. The study was a meta-review, meaning a review of reviews – merging the results of 10 meta-analyses with a total of 43,000 participants. While meta-analysis is a powerful tool, a National Center for Biotechnology Information (NCBI) study cautioned that meta-analyses can be controversial tools that may lead to misleading conclusions in that "decisions made when designing and performing a meta-analysis require personal judgment and expertise, thus creating personal biases or expectations that may influence the result."

The results?

The study concludes that marijuana intoxication produces cognitive deficits in the following areas:

• Decision making;
• Memory and concentration; 
• Suppression of inappropriate responses;
• Learning through reading and listening;
• The time required to finish a mental task.

According to the review, these adverse effects of cannabis consumption begin while it is being consumed and persist afterward. 

See also: Old Weed: What Happens To Marijuana After Five Years Of Storage?

"Our study enabled us to highlight several areas of cognition impaired by cannabis use, including problems concentrating and difficulties remembering and learning, which may have considerable impact on users' daily lives," said the study's co-author Dr. Alexandre Dumais, associate clinical professor of psychiatry at Université de Montréal. "Cannabis use in youth may consequently lead to reduced educational attainment, and, in adults, to poor work performance and dangerous driving. These consequences may be worse in regular and heavy users."

Importance Of The Study 

The study further highlighted how cannabis is the third most consumed psychoactive substance in the world, after alcohol and nicotine, with adolescents and young adults being the most common consumers.

Because of the recent global cannabis legalization trend, which shifts the perceptions of the safety of the plant, the study's authors emphasized the importance of comprehending the cognitive risks associated with marijuana use, especially for adolescents whose brains are undergoing significant developmental changes.

Photo: Courtesy of LeVan Smith III on Unsplash