title: Assessing medication effects in the MTA study using neuropsychological outcomes.
abstract: BACKGROUND
  While studies have increasingly investigated deficits in reaction time (RT) and RT variability in children with attention deficit/hyperactivity disorder (ADHD), few studies have examined the effects of stimulant medication on these important neuropsychological outcome measures.
  
  
  METHODS
  316 children who participated in the Multimodal Treatment Study of Children with ADHD (MTA) completed the Conners' Continuous Performance Test (CPT) at the 24-month assessment point. Outcome measures included standard CPT outcomes (e.g., errors of commission, mean hit reaction time (RT)) and RT indicators derived from an Ex-Gaussian distributional model (i.e., mu, sigma, and tau).
  
  
  RESULTS
  Analyses revealed significant effects of medication across all neuropsychological outcome measures. Results on the Ex-Gaussian outcome measures revealed that stimulant medication slows RT and reduces RT variability.
  
  
  CONCLUSIONS
  This demonstrates the importance of including analytic strategies that can accurately model the actual distributional pattern, including the positive skew. Further, the results of the study relate to several theoretical models of ADHD.
authors: Department of Psychiatry & Behavioral Sciences, Duke University Medical Center, Durham, NC 27710, USA. epste002@mc.duke.edu
authors: Jeffery N
authors: JN
authors: Epstein
authors: C Keith
authors: CK
authors: Conners
authors: Aaron S
authors: AS
authors: Hervey
authors: Simon T
authors: ST
authors: Tonev
authors: L Eugene
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authors: Arnold
authors: Howard B
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authors: Abikoff
authors: Glen
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authors: Elliott
authors: Laurence L
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authors: Greenhill
authors: Lily
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authors: Hechtman
authors: Kimberly
authors: K
authors: Hoagwood
authors: Stephen P
authors: SP
authors: Hinshaw
authors: Betsy
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authors: Hoza
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authors: Jensen
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authors: March
authors: Jeffrey H
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authors: Newcorn
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authors: Pelham
authors: Joanne B
authors: JB
authors: Severe
authors: James M
authors: JM
authors: Swanson
authors: Karen
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authors: Wells
authors: Benedetto
authors: B
authors: Vitiello
authors: Timothy
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authors: Wigal