title: Effects of methylphenidate treatment in children with mental retardation and ADHD: individual variation in medication response.
abstract: OBJECTIVE
  Individual variation in cognitive and behavioral response to methylphenidate (MPH) was investigated in children with mental retardation and attention-deficit/hyperactivity disorder.
  
  
  METHODS
  Twenty-four children (mean age 10.9 years, SD = 2.4) participated in a placebo-controlled, double-blind, crossover trial with 0.15-, 0.30-, and 0.60-mg/kg b.i.d. doses of MPH. Parent and teacher behavioral ratings, as well as cognitive task performance, were assessed at each dose.
  
  
  RESULTS
  Relative to placebo, most children with attention-deficit/hyperactivity disorder and mental retardation showed some degree of behavioral and cognitive improvement with MPH treatment. However, fewer of these children made substantial gains (>30% improvement, relative to placebo) with MPH treatment. At the highest dose, 55% of the children showed substantial behavioral gains and 46% made substantial gains in cognitive task performance. However, there was substantial independence between changes in behavior and changes in cognitive performance.
  
  
  CONCLUSIONS
  At the 0.60-mg/kg MPH dose, more children showed substantial cognitive and behavioral gains than those who showed substantial declines in a ratio of more than 5:1. However, it may be prudent to assess cognitive change as well as behavioral effects because improvements in the former do not necessarily forecast improvements in the latter in children with attention-deficit/hyperactivity disorder and mental retardation.
authors.affiliation: Department of Psychiatry and Behavioral Sciences, University of Texas Medical School at Houston 77030-3497, USA. Deborah.A.Pearson@uth.tmc.edu
authors.forename: Deborah A
authors.initials: DA
authors.lastname: Pearson
authors.forename: David M
authors.initials: DM
authors.lastname: Lane
authors.forename: Cynthia W
authors.initials: CW
authors.lastname: Santos
authors.forename: Charles D
authors.initials: CD
authors.lastname: Casat
authors.forename: Susan W
authors.initials: SW
authors.lastname: Jerger
authors.forename: Katherine A
authors.initials: KA
authors.lastname: Loveland
authors.forename: Laura P
authors.initials: LP
authors.lastname: Faria
authors.forename: Rosleen
authors.initials: R
authors.lastname: Mansour
authors.forename: Jill A
authors.initials: JA
authors.lastname: Henderson
authors.forename: Christa D
authors.initials: CD
authors.lastname: Payne
authors.forename: John D
authors.initials: JD
authors.lastname: Roache
authors.forename: David
authors.initials: D
authors.lastname: Lachar
authors.forename: Lynne A
authors.initials: LA
authors.lastname: Cleveland
mesh_terms: D001289:Attention Deficit Disorder with Hyperactivity / Q000150:complications / Q000188:drug therapy*; D001519:Behavior / Q000187:drug effects; D000697:Central Nervous System Stimulants / Q000008:administration & dosage / Q000494:pharmacology*; D002648:Child; D003071:Cognition / Q000187:drug effects; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008607:Intellectual Disability / Q000150:complications*; D008297:Male; D008774:Methylphenidate / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D000697:Central Nervous System Stimulants; D008774:Methylphenidate