Comorbidity Moderates Response to Methylphenidate in the Preschoolers with Attention-Deficit/Hyperactivity Disorder Treatment Study (PATS)

Abstract

In preschoolers with ADHD, the presence of no or one co-morbid disorder (primarily oppositional defiant disorder) predicted a large treatment response at the same level as has been found in school-aged children, and two co-morbid disorders predicted moderate treatment response; whereas the presence of three or more co-morbid disorders predicted no treatment response to MPH.