title: Olfactory functions and volumetric measures of orbitofrontal and limbic regions in schizophrenia.
abstract: OBJECTIVE
  Olfactory deficits in schizophrenia patients have been suggested to reflect medial temporal and/or prefrontal brain abnormalities. In this study, we examined the relationship between different olfactory functions and volumes of the hippocampus-amygdala complex (HAC) and the orbitofrontal brain region using magnetic resonance imaging (MRI).
  
  
  METHODS
  Thirty-three young men with schizophrenia (DSM-IV) and 40 healthy controls performed unirhinal olfactory assessment including the main olfactory functions (threshold, discrimination, and identification), and odor judgements (intensity, edibility, familiarity, and pleasantness). Volumes of regions in the medial temporal lobe (hippocampus and amygdala) and the prefrontal region (orbitofrontal gray and white matter) were measured on MRI scans.
  
  
  RESULTS
  Compared with controls, patients showed bilaterally impaired thresholds, quality discrimination and identification, as well as edibility judgements. Olfactory deficits were not attributable to smoking, premorbid intelligence, or impaired thresholds. Relative to controls, patients had bilateral reduced hippocampus and amygdala volumes. In patients, smaller hippocampus volumes were associated with poorer olfactory discrimination ability.
  
  
  CONCLUSIONS
  Olfactory deficits in schizophrenia appear to be associated with morphometric abnormalities in the medial temporal rather than the orbitofrontal region (OFR). These results indicate that olfactory quality discrimination deficits are related to structural hippocampus abnormalities. Future studies of genetic and behavioral high-risk samples seem warranted.
authors.affiliation: Department of Psychiatry, Medical University Innsbruck, Austria. claudia.rupp@uibk.ac.at
authors.forename: Claudia I
authors.initials: CI
authors.lastname: Rupp
authors.forename: W Wolfgang
authors.initials: WW
authors.lastname: Fleischhacker
authors.forename: Georg
authors.initials: G
authors.lastname: Kemmler
authors.forename: Christian
authors.initials: C
authors.lastname: Kremser
authors.forename: Robert M
authors.initials: RM
authors.lastname: Bilder
authors.forename: Sergei
authors.initials: S
authors.lastname: Mechtcheriakov
authors.forename: Philip R
authors.initials: PR
authors.lastname: Szeszko
authors.forename: Thomas
authors.initials: T
authors.lastname: Walch
authors.forename: Arne W
authors.initials: AW
authors.lastname: Scholtz
authors.forename: Martina
authors.initials: M
authors.lastname: Klimbacher
authors.forename: Claudia
authors.initials: C
authors.lastname: Maier
authors.forename: Gudrun
authors.initials: G
authors.lastname: Albrecht
authors.forename: Theresia
authors.initials: T
authors.lastname: Lechner-Schoner
authors.forename: Stefan
authors.initials: S
authors.lastname: Felber
authors.forename: Hartmann
authors.initials: H
authors.lastname: Hinterhuber
mesh_terms: D000328:Adult; D000679:Amygdala / Q000002:abnormalities; D005260:Female; D006624:Hippocampus / Q000002:abnormalities; D006801:Humans; D007600:Judgment; D008032:Limbic System / Q000002:abnormalities*; D008279:Magnetic Resonance Imaging; D008297:Male; D009812:Odorants; D000857:Olfaction Disorders / Q000175:diagnosis / Q000209:etiology*; D017397:Prefrontal Cortex / Q000002:abnormalities*; D012559:Schizophrenia / Q000150:complications*; D012684:Sensory Thresholds / Q000502:physiology; D012720:Severity of Illness Index; D013702:Temporal Lobe / Q000002:abnormalities