Brain imaging studies reveal structural and functional abnormalities in the frontal lobes of children with ADHD. This brain region, which is rich in dopamine, is crucial for inhibiting behavior. Compared to their peers without the disorder, children with ADHD tend to have a smaller frontal lobe volume and exhibit reduced activation in this area when performing mental tasks. These neurological differences are thought to be a key explanation for the hyperactive and uncontrolled behaviors characteristic of ADHD.