title: Olfactory processing, sex effects and heterogeneity in schizophrenia.
abstract: BACKGROUND
  Smell identification deficits are associated with negative symptoms in schizophrenia, particularly in males. Far less information is known about the relationship of odor detection sensitivity (acuity) and negative symptoms in schizophrenia, and currently there is a dearth in sex-stratified research specifically examining odor sensitivity and smell identification.
  
  
  METHODS
  Fifty-eight individuals with schizophrenia and 42 healthy comparison subjects were assessed on tests of odor sensitivity, smell identification and cognition. Negative symptoms were assessed with the Positive and Negative Syndrome Scale and the Schedule for the Deficit Syndrome.
  
  
  RESULTS
  In healthy males, increased odor detection sensitivity predicted better smell identification scores. In contrast, male schizophrenia patients showed a significant inverse relationship, in which increased odor sensitivity predicted lower smell identification scores. Odor sensitivity and smell identification were unrelated in both schizophrenia and healthy females. Olfactory processing was strongly linked to negative symptoms, but the relationships differed by sex. Emotional expression deficits were related to odor detection hypersensitivity in female patients, whereas smell identification deficits predicted these emotional deficits in male cases.
  
  
  CONCLUSIONS
  Sex differences in olfactory functioning were identified in healthy subjects and in schizophrenia patients. Smell identification was related to negative symptoms in males with schizophrenia, whereas odor detection sensitivity predicted these features in females. Sex differences should be considered in future analyses that employ odor stimuli for neuropsychiatric research.
authors.affiliation: New York University School of Medicine, Institute for Social and Psychiatric Initiatives, 500 1st Avenue, NBV 22N10, New York, NY 10016, USA. dolores.malaspina@nyumc.org
authors.forename: Dolores
authors.initials: D
authors.lastname: Malaspina
authors.forename: Raymond
authors.initials: R
authors.lastname: Goetz
authors.forename: Andreas
authors.initials: A
authors.lastname: Keller
authors.forename: Julie W
authors.initials: JW
authors.lastname: Messinger
authors.forename: Gerard
authors.initials: G
authors.lastname: Bruder
authors.forename: Deborah
authors.initials: D
authors.lastname: Goetz
authors.forename: Mark
authors.initials: M
authors.lastname: Opler
authors.forename: Susan
authors.initials: S
authors.lastname: Harlap
authors.forename: Jill
authors.initials: J
authors.lastname: Harkavy-Friedman
authors.forename: Daniel
authors.initials: D
authors.lastname: Antonius
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007361:Intelligence Tests; D008297:Male; D008875:Middle Aged; D009812:Odorants; D000857:Olfaction Disorders / Q000175:diagnosis / Q000209:etiology*; D011237:Predictive Value of Tests; D011569:Psychiatric Status Rating Scales; D011618:Psychotic Disorders / Q000150:complications / Q000175:diagnosis / Q000209:etiology; D012559:Schizophrenia / Q000150:complications*; D012684:Sensory Thresholds / Q000502:physiology*; D012727:Sex Characteristics; D012903:Smell / Q000502:physiology; D013223:Statistics as Topic; D014705:Verbal Behavior / Q000502:physiology; D055815:Young Adult