Improvement of executive functions in boys with attention deficit hyperactivity disorder: an open-label follow-up study with once-daily atomoxetine

Abstract

Atomoxetine is efficacious in reducing symptoms of attention deficit hyperactivity disorder (ADHD) but its effect on executive functions needs more investigation. We examined the effect of atomoxetine on a wide range of non-verbal executive functions among 30 drug-naive male patients with DSM-IV ADHD, aged 8-16 yr, in an open-label 12-wk atomoxetine treatment trial. Before administration of atomoxetine, the participants were assessed by psychiatric interviews, the WISC-III, and the tasks involving executive functions of the Cambridge Neuropsychological Test Automated Battery (CANTAB): Intra-dimensional/Extra-dimensional Shifts (IED), Rapid Visual Information Processing (RVIP), Spatial Span (SSP), Spatial Working Memory (SWM), and Stockings of Cambridge (SOC); and reassessed at weeks 4 and 12. All the raw scores of the CANTAB were transformed to z scores based on a normative sample of 180 children aged 8-16 yr. Results showed significant improvement in executive functions after treatment with atomoxetine for 4 wk or 12 wk including improved shifting and flexibility of attention in the IED; improved spatial short-term memory in the SSP; improved sustained attention and increased response inhibition in the RVIP; improved spatial working memory in the SWM; and improved spatial planning and problem solving in the SOC. Our findings suggested that atomoxetine was associated with significant improvement in various non-verbal executive functions among boys with ADHD, in addition to its well-known efficacy in ADHD-related symptom reductions. However, owing to lack of a placebo-controlled trial design, the findings should be interpreted with caution that changes in performance may be due to practice effects.