title: Effects of methylphenidate on subtypes of attention-deficit/hyperactivity disorder.
abstract: OBJECTIVE
  To compare the effects of methylphenidate on attention-deficit/hyperactivity disorder (ADHD) subtypes.
  
  
  METHODS
  Nineteen ADHD/inattentive (ADHD/I) and 22 ADHD/combined (ADHD/C) 6- to 12-year-old children entered a 6-week, double-blind trial of placebo and methylphenidate in divided doses (0.94 +/- 0.02 mg/kg/day = 33.06 +/- 1.40 mg/day). ADHD children received a restricted arithmetic task without medication before the trial and after their noon dose on the last day of each phase. Thirty-four unmedicated controls were tested at comparable time points. Parents and teachers rated ADHD children before and after each phase of the trial; parents rated controls before the study.
  
  
  RESULTS
  Controls had marginally better arithmetic performance than children with ADHD/C who outperformed ADHD/I children. Unmedicated children with ADHD exceeded controls in task-incompatible behaviors during restricted arithmetic. Under methylphenidate, both ADHD subtypes reached control levels of arithmetic performance and task-incompatible behavior. Before the trial, parents rated children with both ADHD subtypes higher than controls on inattention, hyperactivity, and oppositionality/aggression and parents and teachers rated ADHD/C children higher than ADHD/I children on hyperactivity and oppositionality/aggression but not inattention. Methylphenidate lowered parent and teacher ratings of inattention and hyperactivity for those with both ADHD subtypes, but ratings of children with ADHD/C decreased more in hyperactivity and aggression.
  
  
  CONCLUSIONS
  Methylphenidate ameliorated task-incompatible behavior, arithmetic performance, and inattention comparably in both ADHD subtypes, whereas medication reduced hyperactivity and aggression largely in children with ADHD/C.
authors.affiliation: University of Rochester, Rochester, NY 14627-0266, USA. rafael.klorman@rochester.edu
authors.forename: Erin B
authors.initials: EB
authors.lastname: Gorman
authors.forename: Rafael
authors.initials: R
authors.lastname: Klorman
authors.forename: Joan E
authors.initials: JE
authors.lastname: Thatcher
authors.forename: Agneta D
authors.initials: AD
authors.lastname: Borgstedt
mesh_terms: D000374:Aggression / Q000523:psychology; D001288:Attention / Q000187:drug effects; D001289:Attention Deficit Disorder with Hyperactivity / Q000145:classification* / Q000188:drug therapy*; D000697:Central Nervous System Stimulants / Q000627:therapeutic use*; D002648:Child; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008774:Methylphenidate / Q000627:therapeutic use*; D016896:Treatment Outcome
chemical_list: D000697:Central Nervous System Stimulants; D008774:Methylphenidate