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Who Is Affected by Attention Deficit Hyperactivity Disorder (ADHD)

Estimates vary about how many people are affected by attention deficit hyperactivity disorder (ADHD). The accepted standard for diagnosing ADHD is the DSM-IV criteria from the American Psychiatric Association.1 A child's dominant symptoms (inattention, impulsiveness, and/or hyperactivity) are determined and categorized. The condition affects about 3 to 7 out of 100 school-age children in the United States.1

  • Boys are diagnosed with ADHD more often than girls, with a varying ratio of 2:1 to 9:1 depending on the specific type.1
  • Inattention is the most common type of ADHD diagnosed in girls. This type is the least likely to be noticed in the early school years. It may not be detected until late childhood.1 Many girls may not be diagnosed and properly treated for the disorder until later in life.
  • It is not clear how many adults are affected by ADHD. But overall estimates are that about half of children with ADHD continue to have symptoms into adulthood.2 More research is needed in this area.


  1. American Psychiatric Association (2000). Attention-deficit and disruptive behavior disorders. In Diagnostic and Statistical Manual of Mental Disorders, 4th ed., text rev., pp. 85–103. Washington, DC: American Psychiatric Association.

  2. McGough JJ (2005). Adult manifestations of attention-deficit/hyperactivity disorder section of Attention-deficit disorders. In BJ Sadock, VA Sadock, eds., Kaplan and Sadock's Comprehensive Textbook of Psychiatry, 8th ed., vol. 2, pp. 3198–3204. Philadelphia: Lippincott Williams and Wilkins.

ByHealthwise Staff
Primary Medical ReviewerAdam Husney, MD - Family Medicine
Specialist Medical ReviewerLouis Pellegrino, MD - Developmental Pediatrics
Last RevisedFebruary 2, 2012

WebMD Medical Reference from Healthwise

Last Updated: February 02, 2012
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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