Researchers at the University of Michigan analyzed 108 individuals in their early 20s. Seventy-five percent of participants were men, and nearly all were white. The investigators reviewed brain scans at three points over the course of four years.
“Marijuana is the most commonly used illicit drug in the United States and national surveys have shown that the perception of risk of harm from marijuana use has been decreasing over the past five years,” she said. “Our findings challenge this growing perception that marijuana use is not harmful by demonstrating an association between marijuana use and changes in the functioning of the brain reward system over time.”
Read the full article "Over Time, Marijuana Use May Dampen The Brain's Response To Reward" at Forbes.