title: Deficits in prepulse inhibition and habituation in never-medicated, first-episode schizophrenia.
abstract: BACKGROUND
  Prepulse inhibition (PPI) is the normal suppression of the startle reflex when an intense startling stimulus is preceded by a barely detectable prepulse. Habituation of the acoustic startle reflex is decrement in response when the same stimulus is presented repeatedly. These factors have been proposed as neurophysiologic measures of sensorimotor gating or filtering and discussed as trait-linked markers for information-processing deficits in schizophrenia-spectrum disorders. The aim of this study was to examine whether first-episode schizophrenia patients also exhibit deficits in PPI and habituation.
  
  
  METHODS
  Never-medicated male schizophrenic and schizophreniform patients in their first psychotic episode (n=24) were compared with age-matched healthy men (n=21) in an acoustic startle paradigm assessing PPI (30-, 60-, 120-, 240-, and 2000-msec interstimulus intervals) and habituation.
  
  
  RESULTS
  Compared with control subjects, first-episode patients exhibited significant deficits in both PPI in the 60-msec prepulse condition and startle habituation. Patients also exhibited less facilitation in the 2000-msec prepulse condition.
  
  
  CONCLUSIONS
  In combination with other studies, these findings indicate that PPI and habituation may be sensitive intermediate phenotypic markers for information-processing deficits in schizophrenic patients.
authors.affiliation: Department of Research, Psychiatric Services of Aargau Canton, Brugg, Switzerland.
authors.forename: Katja
authors.initials: K
authors.lastname: Ludewig
authors.forename: Mark A
authors.initials: MA
authors.lastname: Geyer
authors.forename: Franz X
authors.initials: FX
authors.lastname: Vollenweider
mesh_terms: D000161:Acoustic Stimulation; D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D006185:Habituation, Psychophysiologic; D006801:Humans; D007266:Inhibition, Psychological; D008297:Male; D013216:Reflex, Startle; D012559:Schizophrenia / Q000503:physiopathology*; D012565:Schizophrenic Psychology