European scientists reported the discovery Tuesday in the journal Translational Psychiatry. Psychologist Simone Kuhn of Ghent University in Belgium and colleagues recruited 154 healthy 14-year-olds in Berlin and divided them into two groups. Twenty-four girls and 52 boys were frequent gamers who played at least nine hours of video games each week. Fifty-eight girls and 20 boys were infrequent gamers, who played less than nine hours a week.
Structural magnetic resonance imaging (MRI) showed differences in the test subjects' brains. Frequent gamers had more gray matter in a portion of the brain known as the left ventral striatum, which affects the interplay of emotions and behavior. Previous research identified striatal function as a "core candidate promoting addictive behavior," the authors wrote.