title: Effects of methylphenidate on inhibitory control in hyperactive children.
abstract: This study investigated the effects of methylphenidate (MPH) on inhibitory control in hyperactive children. A double-blind, placebo-control, within-subject (crossover) design was used in which 12 children, between 6 and 11 years of age, were each tested four times in each drug condition: 0.3 mg/kg and 1.0 mg/kg of methylphenidate, and placebo. Dependent measures included (a) the probability of inhibiting responses to a primary choice reaction time task given a stop signal, on the Stopping Task, and (b) response latency and errors on the Matching Familiar Figures Test (MFFT). MPH improved the efficiency of the central inhibitory mechanism by speeding the inhibitory process, thereby affording the children greater control over their actions and enabling them to increase the probability with which they inhibited responses given a stop signal. MPH increased response latency but did not reduce errors on the MFFT, and observation of the children's task performance highlighted the interpretive problems associated with this task. Performance on both tasks was better at a dosage of 1.0 mg/kg than at 0.3 mg/kg.
authors.affiliation: Department of Psychiatry Research, Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: R
authors.initials: R
authors.lastname: Tannock
authors.forename: R J
authors.initials: RJ
authors.lastname: Schachar
authors.forename: R P
authors.initials: RP
authors.lastname: Carr
authors.forename: D
authors.initials: D
authors.lastname: Chajczyk
authors.forename: G D
authors.initials: GD
authors.lastname: Logan
mesh_terms: D001143:Arousal / Q000187:drug effects; D001288:Attention / Q000187:drug effects*; D001289:Attention Deficit Disorder with Hyperactivity / Q000188:drug therapy*; D002648:Child; D003192:Compulsive Behavior / Q000188:drug therapy; D004193:Discrimination Learning / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007266:Inhibition, Psychological; D008297:Male; D008774:Methylphenidate / Q000627:therapeutic use*; D010364:Pattern Recognition, Visual / Q000187:drug effects; D016032:Randomized Controlled Trials as Topic; D011930:Reaction Time / Q000187:drug effects
chemical_list: D008774:Methylphenidate