title: Caffeine effects on resting-state electrodermal levels in AD/HD suggest an anomalous arousal mechanism.
abstract: The effect of a single oral dose of caffeine was examined in a randomised double-blind placebo-controlled repeated-measures cross-over study. Eighteen children with AD/HD, aged between 8 and 13 years, were individually age- and gender-matched with a control group. All children participated in two sessions, one week apart. Skin conductance level (SCL) from a 3 min eyes-closed epoch, commencing 30 min after ingestion of caffeine or placebo, was examined. Across conditions, mean SCL was lower in the AD/HD group than controls, confirming hypoarousal in AD/HD. Caffeine produced an increase in SCL, and this increase did not differ between the groups. However, arousal increases were dose-dependent in controls, but not in AD/HD. Rather, caffeine-induced arousal increases in the AD/HD group were positively related to their hyperactivity/impulsivity levels. This suggests an anomalous arousal mechanism in AD/HD functionally related to impairment in one symptom dimension.
authors.affiliation: Brain & Behaviour Research Institute and School of Psychology, University of Wollongong, Australia. rbarry@uow.edu.au
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Barry
authors.forename: Adam R
authors.initials: AR
authors.lastname: Clarke
authors.forename: Rory
authors.initials: R
authors.lastname: McCarthy
authors.forename: Mark
authors.initials: M
authors.lastname: Selikowitz
authors.forename: Brett
authors.initials: B
authors.lastname: MacDonald
authors.forename: Franca E
authors.initials: FE
authors.lastname: Dupuy
mesh_terms: D000293:Adolescent; D000704:Analysis of Variance; D001289:Attention Deficit Disorder with Hyperactivity / Q000188:drug therapy* / Q000503:physiopathology*; D002110:Caffeine / Q000627:therapeutic use*; D016022:Case-Control Studies; D000697:Central Nervous System Stimulants / Q000627:therapeutic use*; D002648:Child; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D005712:Galvanic Skin Response / Q000187:drug effects*; D006801:Humans; D008297:Male; D011930:Reaction Time / Q000187:drug effects; D012146:Rest / Q000502:physiology*
chemical_list: D000697:Central Nervous System Stimulants; D002110:Caffeine