DSM-IV-TR criteria for ADHD require at least six of nine symptoms of inattention and/or hyperactivity impulsivity to be endorsed. Symptoms associated with significant impairment in different settings by 7 years of age. As detailed in the following sections subjects were not initially identified according to DSM-IV-TR criteria but only those subjects meeting full diagnostic criteria (of any DSM-IV-TR ADHD subtype) were enrolled in this genome-wide association study.
