Stimulant drug response in the predominantly inattentive and combined subtypes of attention-deficit/hyperactivity disorder.

Objective: This study compared the methylphenidate (MPH) dose-response profiles of children with the Predominantly Inattentive (PI) and Combined (CB) subtypes of attention-deficit/hyperactivity disorder (ADHD). It is the first such study to enroll a sample comprised exclusively of children, all but one of whom had no prior exposure to ADHD medications.

Method: The design was a double-blind crossover with 1-week exposures to placebo and low, medium, and high, fixed, three times daily (t.