Children with ADHD and motor dysfunction compared with children with ADHD only.

The purpose of this study was to identify group differences in children with attention-deficit-hyperactivity disorder and motor dysfunction (ADHD-MD) and ADHD only, and to evaluate the medication responsiveness of ADHD-MD. Sixty-three children (49 males and 14 females; mean age 9 years 10 months, SD 2 years 10 months) underwent a triple blind, placebo-controlled crossover study evaluating two dose levels of methylphenidate (0.3 mg/kg and 0.