Evidence of A Pharmacological Dissociation Between The Robust Effects of Methylphenidate on Adhd Symptoms and Weaker Effects on Working Memory

Authors

  • Joseph Biederman Clinical and Research Programs in Pediatric Psychopharmacology and Adult ADHD, Massachusetts General Hospital, Fruit Street, Warren, Boston, MA, USA; Harvard Medical School, Fruit Street, Warren, Boston, MA, USA
  • James Chan Clinical and Research Programs in Pediatric Psychopharmacology and Adult ADHD, Massachusetts General Hospital, Fruit Street, Warren, Boston, MA, USA
  • Thomas J Spencer Clinical and Research Programs in Pediatric Psychopharmacology and Adult ADHD, Massachusetts General Hospital, Fruit Street, Warren, Boston, MA, USA; Harvard Medical School, Fruit Street, Warren, Boston, MA, USA
  • K Yvonne Woodworth Clinical and Research Programs in Pediatric Psychopharmacology and Adult ADHD, Massachusetts General Hospital, Fruit Street, Warren, Boston, MA, USA
  • Tara Kenworthy Clinical and Research Programs in Pediatric Psychopharmacology and Adult ADHD, Massachusetts General Hospital, Fruit Street, Warren, Boston, MA, USA
  • Ronna Fried Clinical and Research Programs in Pediatric Psychopharmacology and Adult ADHD, Massachusetts General Hospital, Fruit Street, Warren, Boston, MA, USA; Harvard Medical School, Fruit Street, Warren, Boston, MA, USA
  • Pradeep Bhide Florida State University College of Medicine, West Call Street, Tallahassee, FL, USA
  • Stephen V Faraone SUNY Upstate Medical University, Weiskotten Hall, Syracuse, NY, USA

DOI:

https://doi.org/10.18488/journal.83/2015.1.2/83.2.43.53

Abstract

Working memory (WM) deficits often co-occur with, but do not define, attention deficit hyperactivity disorder (ADHD). Preclinical and neuroimaging studies show that ADHD and WM deficits are dissociated at the level of individual dopamine receptor function. We hypothesized that there would also be a pharmacological dissociation of the effects of stimulants on ADHD and WM. ADHD subjects were derived from three prospective clinical trials involving treatment with OROS methylphenidate for at least 6 weeks. Subjects were adolescents and adults with DSM-IV ADHD with systematic assessments of WM and ADHD symptoms. Cohen’s d was used to evaluate effect size between baseline and week 6 for all assessments, and Pearson correlations were used to evaluate the relationship between assessments at baseline and between change scores for assessments from baseline to week 6. Cohen's d estimates for the Cambridge Neuropsychological Test Automated Battery spatial working memory measures differed significantly by 1.8 standard deviations (t= -10.8, df= 70, p < 0.001) and 1.9 standard deviations (t= -11.1, df= 70, p < 0.001) for the strategy and total between errors subcategories respectively. Confidence intervals did not overlap with those of the Adult ADHD Investigator Symptom Rating Scale (AISRS). A similar effect was observed for changes in AISRS and the Behavior Rating Inventory of Executive Function working memory scale where the Cohen's d estimates differed significantly by 1.1 standard deviations (t= -2.5, df= 137, p = 0.015) and confidence intervals did not overlap. These findings provide further evidence for the dissociation between ADHD and WM deficits.

Keywords:

ADHD, Working memory, Dissociation, Pharmacology, Methylphenidate

Abstract Video

Published

2015-06-15

How to Cite

Biederman, J. ., Chan, J. ., Spencer, T. J., Woodworth, K. Y. ., Kenworthy, T. ., Fried, R. ., Bhide, P. ., & Faraone, S. V. (2015). Evidence of A Pharmacological Dissociation Between The Robust Effects of Methylphenidate on Adhd Symptoms and Weaker Effects on Working Memory. Journal of Brain Sciences, 1(2), 43–53. https://doi.org/10.18488/journal.83/2015.1.2/83.2.43.53

Issue

Vol. 1 No. 2 (2015)

Section

Articles