October 2018

Marijuana use causes more long-term damage to teen brains than alcohol use, according to a new study entitled “A Population-Based Analysis of the Relationship Between Substance Use and Adolescent Cognitive Development.”

The study – completed by researchers at the University of Montreal – followed 3,800 Montreal teens over the course of four years. As part of the study, teen participants were questioned about their marijuana and alcohol use, and took computer-based cognitive tests.

They found that marijuana had more of an effect on the teens’ skills, memory and behavior than alcohol… Even after students reported stopping marijuana, their cognition did not improve.

“Cannabis causes cognitive impairment and delayed cognitive development in adolescents," Patricia Conrad, the lead author and professor of psychiatry at the University of Montreal, told NBC News. “This study focuses on the neuropsychological effects of cannabis. We think it’s important because it is linked to how someone functions in life.”

The findings were published in the American Journal of Psychiatry. 

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