" the dysregulation of the body’s neurobiological system, that impairs one’s ability to pay selective attention to one’s surroundings. The world becomes a land without street signs, the individual a car in bad need of a tune-up. The vastness of the attentional system partially accounts for the variation of ADD “types.” Where one individual needs an oil change, the next needs spark plugs replaced. Where one individual is withdrawn and overwhelmed by stimuli, the next is hyperactive and can’t get enough stimuli. Where one is frequently anxious, the other is depressed. To compensate, each develops his or her own coping strategies that developmentally add to, or subtract from, the brain’s various subsystems. So Mr. A becomes a stand-up comedian, and manic. Ms. B becomes an architectural wizard with obsessive-compulsive traits. Their offspring become a sculptor and a stunt pilot. None of them can balance their checkbook. And all of them wish they had more time in the day. With such diversity in the disorder, "

― Edward M. Hallowell , Driven to Distraction: Recognizing and Coping with Attention Deficit Disorder from Childhood Through Adulthood