Response to atomoxetine in boys with high-functioning autism spectrum disorders and attention deficit/hyperactivity disorder

Aim: To study the efficacy and tolerability of atomoxetine in high‐functioning boys with autism spectrum disorders (ASD) and comorbid attention deficit/hyperactivity disorder (AD/HD). Methods: Fourteen boys (age 7–17) participated in a 10‐week open‐label study. Atomoxetine doses were 0.5 mg/kg/day in week 1 and 1.2–1.4 mg/kg/day in weeks 2–10. Changes in AD/HD symptoms were measured by the AD/HD Rating Scale, and global improvements by the Clinical Global Improvement Scale. Both measures were used to assess drug response. Assessments were done at baseline and at weeks 2, 4, 6 and 10. Teacher ratings were done at baseline and 10 weeks. Results: There were significant reductions in AD/HD symptoms rated by parents (p < 0.005) and by teachers (p < 0.05). One participant was rated as ‘Much improved’, five as ‘Moderately improved’, seven as ‘Minimally improved’, and one as ‘Unchanged or worse’. Seven subjects were classified as clinical responders. The most common adverse events were nausea and headache. Two participants discontinued treatment. Conclusion: Seven out of 14 boys with high‐functioning ASD and comorbid AD/HD showed significant reductions in AD/HD symptoms and were classified as responders to atomoxetine. Most children tolerated the drug well.