Atomoxetine as an adjunct therapy in the treatment of co-morbid attention-deficit/hyperactivity disorder in children and adolescents with bipolar I or II disorder.

Background: Atomoxetine has been proposed to be effective for treating co-morbid attention-deficit/hyperactivity disorder (ADHD) in children with bipolar disorder (BPD) without destabilizing mood. We conducted an 8-week, open label study to study the efficacy and tolerability of adjunct atomoxetine in euthymic children and adolescents with BPD and ADHD.

Methods: We evaluated 12 youth aged 6-17 years (mean = 11.3 years; 7 males) with a diagnosis of BPD I or II and ADHD. Subjects were euthymic at baseline and taking at least one mood stabilizer or antipsychotic. Primary outcome measure was the ADHD Rating Scale-IV (ADHD-RS-IV) (response = 25% decrease; remission = 40% decrease). Secondary outcome measures were change in Young Mania Rating Scale (YMRS) and Children's Depression Rating Scale (CDRS).

Results: In primary outcome criteria, 8 (67%) were responders and 6 (50%) were remitters by ADHD-RS criteria. There was a significant decrease in ADHD-RS scores over the study (p < 0.0001; Cohen d = 2.18, effect size = 0.73). YMRS and CDRS scores did not change significantly from baseline to week 8. No subjects experienced a manic or mixed episode during the study, but 2 subjects were discontinued early due to worsening of mood symptoms.

Conclusions: We found atomoxetine to be efficacious in treating symptoms of ADHD in children and adolescents with BPD taking mood stabilizers or antipsychotics. It is unclear whether symptomatic worsening of 2 subjects was due to atomoxetine or the natural course of illness. Placebo-controlled studies are needed to clarify the role of atomoxetine in this population.