Fourteen-year-olds who were frequent video gamers had more gray matter in the rewards center of the brain than peers who didn't play video games as much -- suggesting that gaming may be correlated to changes in the brain much as addictions are.

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.