Objective: The present study examined the effects of atomoxetine (ATX) on attention deficit/hyperactivity disorder (ADHD) symptoms and autistic features in children with autistic spectrum disorders (ASD).
Method: The files of children with confirmed ASD and ADHD, who had been on ATX treatment, were examined. Fourty-two individuals (33 males and 9 females, age range 6-17 years, mean: 10.0±3.5) were selected. Thirty-three of the children have already been taking other psychotrophic medications, which were not changed during the ATX treatment. All patient files provided information about severity of symptoms, improvement in clinical features and observed side effects using the Clinical Global impressions-improvement scale (CGI-I), DSM-IV based ADHD rating scale (ADHDRS-IV), Aberrant Behavior Checklist and Barkley Stimulant Side Effect Rating Scales at baseline, in week 4 and week 12. Autistic symptoms were rated via the Childhood Autism Rating Scale. ATX was started with a dose of 0.3-0.5 mg/kg/day, titrated slowly to 1-1.2 mg/kg/day in 4 weeks, and the dose was adjusted to 1-1.4 mg/kg/day according to clinical opinion.
Results: ATX was well tolerated with the exception of 6 patients (14%), who stopped medication after the 4th week visit. Among these subjects efficacy data were treated by using the last observation carried forward model. Twenty-two subjects (52.4%) were considered responders to treatment with a CGI-improvement of “very much improved” or “much improved”. On the parent rated ADHDRS-IV, there was significant reduction from baseline to week 4 and from week 4 to week 12 in inattention, hyperactivity and impulsivity. Fifty percent, 42.9% and 50% of the patients showed >=25% improvement in inattention, hyperactivity and impulsivity by week 12, respectively. Decrease was significant in the hyperactivity and social withdrawal subscales of the parent reported ABC and 52.4% and 45.2% of the patients showed >=25% improvement, respectively. No significant change was reported for stereotypic, self-mutilative and other problem behaviours. Responders (n=22) were not significantly different from non-responders (n=20) in terms of age, gender, ASD type, intellectual and language level, baseline CGI severity, level of autistic symptoms and presence of epilepsy. The most common side effects were irritability, decrease in appetite, drowsiness, sleep problems, moodiness. Six patients stopped taking medications due to lack of efficacy, increased motor activity and talkativeness, irritability, temper outbursts and increased blood pressure.
Conclusions: ATX appears to be safe and effective for the core symptoms of ADHD as well as withdrawal in children with ASD. None of those clinical and demographic parameters helped to predict the responders in our sample.