ADHD is the most common neurodevelopment disorder of childhood, affecting between 5% and 10% of school-age children and 4.4% of adults (Kessler et al., 2005). There remains controversy over this disorder because of the lack of any biological diagnostic test, the frequency of salient symptoms (inattention, restlessness, and impulsivity) in the general population, the good long-term outcome for about half of childhood cases, and the possible overuse of stimulant drug treatment.
