A 10-year study by National Institute of Mental Health (NIMH) scientists has found that brains of children and adolescents with Attention Deficit Hyperactivity Disorder (ADHD) are 3-4 percent smaller than those of children who don't have the disorder – and that medication treatment is not the cause. Indeed, in this first major study to scan previously never-medicated patients, they found "strikingly smaller" white matter volumes in children who had not taken stimulant drugs. Still, the course of brain development in the ADHD patients paralleled that of normal subjects, suggesting that whatever caused the disorder happened earlier. Drs. Xavier Castellanos, Judith...