Treatment of attention deficit hyperactivity disorder in children: Predictors of treatment outcome

Objective: The present study investigated the predictive power of anxiety, IQ, severity of
ADHD and parental depression on the outcome of treatment in children with ADHD. Method: Fifty children with ADHD (ages 8-12) were randomized to a 10-week treatment of methylphenidate or to a treatment of methylphenidate combined with multimodal behavior therapy. Prior to treatment predictors were assessed. Outcome was assessed separately
for parents and teachers on a composite measure of inattentive, hyperactive, oppositional- and conduct disorder symptoms.
Results: There was neither a significant difference between the two treatments at baseline nor did treatment condition predict outcome. Therefore the data were collapsed across the two treatments. A combination of anxiety and IQ predicted teacher-rated outcome, explaining 18% of the variance. Higher anxiety and higher IQ’s indicated better treatment
outcome. There were no significant predictors of the parent-rated outcome.
Conclusions: This study showed a small but significant predictive effect of IQ and anxiety on treatment outcome in children with ADHD. Clinical implications: This study supports
the idea that for the treatment of ADHD children with comorbid anxiety and higher IQ respond better to the two most used treatments for ADHD.