title: Habituation of the blink reflex in first-episode schizophrenia, psychotic depression and non-psychotic depression.
abstract: OBJECTIVE
  Electrophysiological recording of the electrically elicited blink reflex is the most reliable method of investigating habituation of the startle reflex. The purpose of this study was to compare the habituation and the late R3-component of the blink reflex between control subjects (N=19) and first-episode patients with schizophrenia (N=17), psychotic depression (N=23), and severe non-psychotic depression (N=25).
  
  
  METHODS
  The blink reflex was evoked by electrical stimulation of the supraorbital nerve, and the deficient habituation of the R2i-component was measured with a computer-assisted integral area measurement. Prefrontal executive function of the patients was assessed with the Wisconsin Card Sorting Test. Current psychiatric symptoms were assessed with the Brief Psychiatric Rating Scale, the Hamilton Depression Scale, the Positive and Negative Syndrome Scale, and the Calgary Depression Scale.
  
  
  RESULTS
  Deficient habituation of the blink reflex and occurrence of the late R3 component were associated both with a previous diagnosis of psychotic disorder and with the presence of current psychosis. The sensitivity and specificity of the abnormal habituation of the blink reflex in detecting psychotic disorder were 0.50 and 0.80, respectively. The abnormalities of the blink reflex were not associated with psychotropic medication. In schizophrenic patients, defective habituation of the blink reflex was associated with negative and cognitive symptoms, and in depressive patients with the presence of delusions.
  
  
  CONCLUSIONS
  The deficient habituation of the blink reflex and occurrence of the late R3 component seem to be both trait and state markers of a psychotic disorder. The results suggest that schizophrenia and psychotic depression share some common neurobiological mechanisms involved in the modulation of the startle reflex.
authors.affiliation: Department of Psychiatry, University of Turku, Kunnallissairaalantie 20, FIN-20700, Turku, Finland. tero.taiminen@utu.fi
authors.forename: T
authors.initials: T
authors.lastname: Taiminen
authors.forename: S
authors.initials: S
authors.lastname: Jääskeläinen
authors.forename: T
authors.initials: T
authors.lastname: Ilonen
authors.forename: H
authors.initials: H
authors.lastname: Meyer
authors.forename: H
authors.initials: H
authors.lastname: Karlsson
authors.forename: H
authors.initials: H
authors.lastname: Lauerma
authors.forename: K M
authors.initials: KM
authors.lastname: Leinonen
authors.forename: E
authors.initials: E
authors.lastname: Wallenius
authors.forename: A
authors.initials: A
authors.lastname: Kaljonen
authors.forename: R K
authors.initials: RK
authors.lastname: Salokangas
mesh_terms: D000328:Adult; D000341:Affective Disorders, Psychotic / Q000175:diagnosis / Q000503:physiopathology*; D001143:Arousal / Q000502:physiology; D001767:Blinking / Q000502:physiology*; D003391:Cranial Nerves / Q000503:physiopathology; D003865:Major Depressive Disorder / Q000175:diagnosis / Q000503:physiopathology*; D004298:Dopamine / Q000502:physiology; D004558:Electric Stimulation; D005260:Female; D006185:Habituation, Psychophysiologic / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D009915:Orbit / Q000294:innervation; D017397:Prefrontal Cortex / Q000503:physiopathology; D011569:Psychiatric Status Rating Scales; D012016:Reference Values; D013216:Reflex, Startle / Q000502:physiology; D012559:Schizophrenia / Q000175:diagnosis / Q000503:physiopathology*
chemical_list: D004298:Dopamine