title: Autonomic abnormalities in schizophrenia. State or trait indicators?
abstract: BACKGROUND
  Tonic electrodermal measures have been widely used to index autonomic abnormalities in schizophrenia, whereas phasic electrodermal nonresponsiveness has been frequently used to index attentional orienting abnormalities. The primary objective of the present study was to assess whether these electrodermal abnormalities are episode indicators or vulnerability indicators.
  
  
  METHODS
  Twenty patients with a recent first episode of schizophrenia were tested during symptomatically remitted states and psychotic states. Twenty demographically matched normal controls were tested at two comparable intervals. Testing for stability of abnormalities across remitted and psychotic states allowed us to determine whether tonic and phasic electrodermal measures qualify as episode indicators or vulnerability indicators.
  
  
  RESULTS
  Tonic electrodermal activity was abnormally elevated only during the psychotic state, which indicates that it is an episode indicator in schizophrenia. Phasic hyporesponsiveness relative to levels of general activation was present in both the remitted and the psychotic states, most strikingly during the psychotic state, and the proportion of patients who were electrodermally nonresponsive tended to be abnormally high during the remission test.
  
  
  CONCLUSIONS
  Tonic electrodermal hyperarousal appears to be a state-sensitive episode indicator, whereas phasic electrodermal hyporesponsiveness to innocuous stimuli relative to activation level appears to be a mediating vulnerability factor.
authors.affiliation: Department of Psychology, University of Southern California.
authors.forename: M E
authors.initials: ME
authors.lastname: Dawson
authors.forename: K H
authors.initials: KH
authors.lastname: Nuechterlein
authors.forename: A M
authors.initials: AM
authors.lastname: Schell
authors.forename: M
authors.initials: M
authors.lastname: Gitlin
authors.forename: J
authors.initials: J
authors.lastname: Ventura
mesh_terms: D000328:Adult; D000553:Ambulatory Care; D001143:Arousal / Q000502:physiology*; D001288:Attention / Q000502:physiology; D005260:Female; D005712:Galvanic Skin Response / Q000502:physiology*; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D009949:Orientation / Q000502:physiology; D012107:Research Design; D012559:Schizophrenia / Q000175:diagnosis* / Q000503:physiopathology; D012565:Schizophrenic Psychology