Researchers found that people who had used marijuana for 12 years, on average, showed greater activity in the brain’s reward system when they looked at pictures of objects used for smoking marijuana than when they looked at pictures of a natural reward — their favorite fruits.
“This study shows that marijuana disrupts the natural reward circuitry of the brain, making marijuana highly salient to those who use it heavily,” study author Dr. Francesca Filbey, an associate professor of behavioral and brain science at the University of Texas at Dallas, said in a statement. “In essence, these brain alterations could be a marker of transition from recreational marijuana use to problematic use.”