Five year National Institute of Mental Health study of > 400 ADHD-diagnosed and non-ADHD teenagers – One of the largest of its kind ever to be funded. This paid study uses safe, non-invasive functional Magnetic Resonance Imaging (fMRI) to measure brain function during tests of the brain’s reward system. The goal is to learn if Attention Deficit Hyperactivity Disorder actually is a collection of different disorders that need different treatments.