Long-Term, Open-Label Study of the Safety and Efficacy of Atomoxetine in Adults With Attention-Deficit/Hyperactivity Disorder: An Interim Analysis

Background: Attention-deficit/hyperactivity disorder (ADHD) is an early-onset neuropsychiatric disorder that affects 3% to 7% of school-age children and 4% of adults. Its pathophysiology is thought to involve the dopaminergic and noradrenergic pathways associated with attention control and impulsivity. These symptoms have largely been defined in the childhood population, but the course of the condition and expression in the adult population are not as well characterized.

Method: This is an ongoing, 3-year, open-label study consisting of adults with DSM-IV ADHD who were previously enrolled in 1 of 2 double-blind, acute-treatment studies of atomoxetine. The results of the interim analysis reported here were derived from the study of 384 patients at 31 sites who had been studied for a period of up to 97 weeks. The primary efficacy measure was the Conners’ Adult ADHD Rating Scale-Investigator Rated: Screening Version (CAARS-Inv:SV) total ADHD symptom score. In addition, safety, adverse events, and vital sign measurements were assessed.

Results: Significant improvement was noted with atomoxetine therapy, with mean CAARS-Inv:SV total ADHD symptom scores decreasing 33.2% from 29.2 (baseline of open-label therapy) to 19.5 (endpoint of open-label therapy) (p < .001). Similar and significant decreases were noted for the secondary efficacy measures. Adverse events consisted primarily of pharmacologically (noradrenergic) expected effects, such as increases in heart rate and blood pressure and a slight decrease in weight.

Conclusion: The results of this interim analysis of an ongoing, open-label study of adults with ADHD support the long-term efficacy, safety, and tolerability of atomoxetine for the treatment of adult ADHD.