title: Effects of methylphenidate on olfaction and frontal and temporal brain oxygenation in children with ADHD.
abstract: OBJECTIVE
  Olfaction and attention-deficit-/hyperactivity disorder (ADHD) are mediated by dopamine metabolism and fronto-temporal functioning converging in recent findings of increased olfactory sensitivity in children with ADHD modulated by methylphenidate (MPH) and altered frontal and temporal oxygenation in adults with ADHD.
  
  
  METHODS
  We investigated olfactory sensitivity, discrimination, and identification (Sniffin' Sticks) in 27 children and adolescents with ADHD under chronic MPH medication and after a wash-out period of at least 14 half-lives in balanced order and 22 controls comparable for handedness, age, and intelligence. In addition, inferior frontal and temporal oxygenation was measured by means of functional near-infrared spectroscopy (fNIRS) during the presentation of 2-phenylethanol. Group differences in regard to sex distribution were statistically controlled for by analysis of covariance.
  
  
  RESULTS
  Patients did not differ from controls in any olfactory domain under treatment with MPH. Cessation of medication led to a significant increase in olfactory discrimination. Controls displayed typical inferior frontal and temporal brain activity in response to passive olfactory stimulation, while brain oxygenation was diminished in the patient group when assessed without medication. Under medication ADHD patients showed a trend for a normalisation of brain activity in the temporal cortex.
  
  
  CONCLUSIONS
  The here reported effects of MPH cessation on olfactory discrimination and frontal and temporal oxygenation along with previous findings of increased olfactory sensitivity in medication-naïve ADHD children and its normalisation under chronic MPH treatment lead to the conclusion that MPH exerts differential chronic effects vs. acute cessation effects on altered olfactory function in ADHD. These effects are most probably mediated by modulation of the dopaminergic system.
authors.affiliation: Department of Psychiatry, Psychosomatics and Psychotherapy, University of Regensburg, Germany. martin.schecklmann@medbo.de
authors.forename: Martin
authors.initials: M
authors.lastname: Schecklmann
authors.forename: Matthias
authors.initials: M
authors.lastname: Schaldecker
authors.forename: Susanne
authors.initials: S
authors.lastname: Aucktor
authors.forename: Julia
authors.initials: J
authors.lastname: Brast
authors.forename: Katharina
authors.initials: K
authors.lastname: Kirchgässner
authors.forename: Andreas
authors.initials: A
authors.lastname: Mühlberger
authors.forename: Andreas
authors.initials: A
authors.lastname: Warnke
authors.forename: Manfred
authors.initials: M
authors.lastname: Gerlach
authors.forename: Andreas J
authors.initials: AJ
authors.lastname: Fallgatter
authors.forename: Marcel
authors.initials: M
authors.lastname: Romanos
mesh_terms: D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000188:drug therapy* / Q000378:metabolism / Q000523:psychology; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D016022:Case-Control Studies; D002648:Child; D018765:Dopamine Uptake Inhibitors / Q000494:pharmacology*; D005260:Female; D005625:Frontal Lobe / Q000378:metabolism; D006801:Humans; D008297:Male; D008774:Methylphenidate / Q000494:pharmacology*; D009483:Neuropsychological Tests; D010100:Oxygen / Q000378:metabolism*; D012903:Smell / Q000187:drug effects*; D019265:Spectroscopy, Near-Infrared; D013702:Temporal Lobe / Q000378:metabolism
chemical_list: D018765:Dopamine Uptake Inhibitors; D008774:Methylphenidate; D010100:Oxygen