Efficacy and safety of atomoxetine in childhood attention-deficit/hyperactivity disorder with comorbid oppositional defiant disorder.

OBJECTIVE

To compare the safety and efficacy of atomoxetine, a selective inhibitor of the norepinephrine transporter, versus placebo in Attention-Deficit/Hyperactivity Disorder (ADHD) patients with comorbid Oppositional Defiant Disorder (ODD).

METHODS

A subset analysis of 98 children from two identical, multi-site, double-blind, randomized, placebo-controlled trials involving 9 weeks of treatment with atomoxetine or placebo was conducted. Patients met DSM-IV ADHD criteria. ODD was diagnosed with the Diagnostic Interview for Children and Adolescents-IV (DICA-IV; Reich, Weiner, and Herjanic, 1997). ADHD severity was assessed with the ADHD Rating Scale-IV-Parent Version: Investigator Administered and Scored (ADHD-RS-IV-Parent:lnv; DuPaul, Power, Anastopoulos, and Reid, 1998); the short version of the Conners' Parent Rating Scales-Revised (CPRS-R:S; Conners, 2000); and the Clinical Global Impressions of ADHD Severity (CGI-ADHD-S; Guy, 1976). Clinical response was defined as a > or = 25% reduction in ADHD-RS-IV-Parent:lnv total score.

RESULTS

ADHD-RS-IV-Parent:lnv, CGI-ADHD-S, and three CPRS-R:S subscale scores improved markedly with atomoxetine treatment. However, a decrease in the CPRS-R:S Oppositional subscore for atomoxetine-treated patients was not significantly greater than scores for placebo-treated patients. Clinical response rates were 65.4% in the atomoxetine group, and 36.4% in the placebo group (p = .007).

CONCLUSION

Atomoxetine was effective for the treatment of ADHD in patients with comorbid ODD. It did not significantly reduce the severity of ODD symptoms, and was well tolerated by the patients.