Objectives: To examine behavioral differences between children with attention-deficit hyperactivity disorder (ADHD) and tics and their peers and the extent to which methylphenidate (0.1, 0.3, and 0.5 mg/kg) normalized the behavior of probands and indirectly influenced the behavior of peers (treatment spillover).
Method: Thirty-four prepubertal children with ADHD and chronic tic disorder (who were participating in a double-blind, placebo-controlled methylphenidate evaluation) and their peers were observed for approximately 20 hours in the school setting (classroom seatwork activities, lunchroom, and playground).
Results: Children with ADHD and tics were more inattentive and more disruptive in the classroom and more aggressive in all school settings than their peers. Although treatment with methylphenidate made probands less easily distinguished from their peers (normalization), many children still scored in the deviant range for at least one ADHD behavior when receiving the 0.5-mg/kg dose. There was little evidence that peer behavior improved as a function of the proband's dose of medication.
Conclusions: Although conventional doses of methylphenidate produced dramatic clinical improvement in ADHD-related behavior, complete behavioral normalization is often not attained.