Over at Retrospectacle, Shelley has a great post on the science of ADHD. I admit to being a healthy skeptic about this for years, but apparently there really is some solid science behind it:
"ADHD affects from 5-10% of children and adolescents, with boys 8 times more likely than girls to have it. The disorder is marked by an inability to focus attention and hyperactive/impulsive behavior. Often these symptoms are paired with poor social skills and difficulties at school, which makes for a very complex situation."