Response of children with ADHD to methylphenidate: interaction with internalizing symptoms.

OBJECTIVE

The purpose of this study was to examine differences in methylphenidate (MPH) response between groups of children with attention-deficit hyperactivity disorder (ADHD) who exhibited varying degrees of internalizing symptoms.

METHOD

A sample of 40 children with ADHD was subdivided into three groups based on the severity of comorbid internalizing symptoms. Differential effects of three doses of MPH (5 mg, 10 mg, 15 mg) were evaluated in a double-blind, placebo-controlled fashion using multiple outcome measures across home, school, and clinic settings.

RESULTS

Children with ADHD and comorbid internalizing symptoms were significantly less likely to respond positively to MPH than were their noninternalizing counterparts according to teacher ratings and behavioral observations during a clinic-based academic task.

CONCLUSIONS

Children who exhibit comorbid symptoms of ADHD and internalizing disorder are less likely to respond to MPH in classroom settings and on academic tasks. A significant minority of children with comorbid conditions may be at a higher risk for an adverse medication response relative to patients with ADHD who are not exhibiting internalizing symptoms. Further research is necessary to delineate the characteristics of possible adverse responders.