An analysis of data from the 2003 National Survey of Children's Health (NSCH) found that  approximately 4.4 million children aged 4--17 years were reported to have a history of ADHD diagnosis; of these, 2.5 million (56%) were reported to be taking medication for the disorder.

In 2003, approximately 7.8% (4,418,000) of U.S. children aged 4--17 years had ever had ADHD diagnosed. ADHD diagnosis was reported approximately 2.5 times more frequently among males than females.

Excerpts from The Morbidity and Mortality Weekly Report (MMWR), by the Centers for Disease Control and Prevention (CDC).