Attention Deficit Disorder With and Without Hyperactivity: Clinical Response to Three Dose Levels of Methylphenidate

The response of 23 children with attention deficit disorder (ADD) with hyperactivity (+H) and 17 children with ADD without hyperactivity (-H) to three doses of methylphenidate (5, 10, and 15 mg twice a day) was evaluated in a triple-blind, placebo-controlled cross-over design using parent and teacher ratings of behavior, laboratory tests of ADD symptoms, and behavioral observations during academic performance. Results indicated that the children with ADD+H were rated as having more pervasive behavioral problems at home and more pervasive and severe conduct problems at school than the children with ADD-H. Laboratory tests found the children with ADD+H to be impaired in behavioral inhibition and vigilance whereas children with ADD-H were more impaired in the consistent retrieval of verbally learned material Drug effects were noted on the parent and teacher ratings and on most laboratory measures, with all three doses typically producing significant changes but rarely differing among themselves in effectiveness. The groups were not found to differ significantly on any measures in their response to methylphenidate. However, more children with ADD-H were clinically judged as having either no clinical response (24%) or responding best to the low dose (35%) of medication. In contrast, most ADD+H (95%) children were judged to be positive responders and most were recommended to receive the moderate to high dose (71%).