title: Neurobiological measures of schizotypal personality disorder: defining an inhibitory endophenotype?
abstract: OBJECTIVE
  Subjects with schizotypal personality disorder demonstrate deficits in inhibition when assessed on prepulse inhibition, P50 suppression, and antisaccade paradigms. This study determined if distinct subgroups of subjects with schizotypal personality disorder could be identified on the basis of performance on these measures and whether endophenotypes could be defined for future genetic study by using measures of inhibitory function.
  
  
  METHODS
  Prepulse inhibition, P50 suppression, and antisaccade paradigms were assessed in 21 subjects with schizotypal personality disorder.
  
  
  RESULTS
  Seven subjects with schizotypal personality disorder had deficits on each paradigm; seven had no deficits on any paradigm. P50 and antisaccade deficits were present in five of the same subjects and significantly correlated.
  
  
  CONCLUSIONS
  These results suggest that P50 and antisaccade performance reflects a common endophenotype and that prepulse inhibition identifies a separate endophenotype reflecting different neurobiological substrate(s) in subjects with schizotypal personality disorder. This pattern may generalize to schizophrenia spectrum disorder patients.
authors: Department of Psychiatry, University of California, San Diego, La Jolla, 92093-0810, USA. kcadenhead@ucsd.edu
authors: Kristin S
authors: KS
authors: Cadenhead
authors: Gregory A
authors: GA
authors: Light
authors: Mark A
authors: MA
authors: Geyer
authors: Jennifer E
authors: JE
authors: McDowell
authors: David L
authors: DL
authors: Braff
mesh_terms: D000161:Acoustic Stimulation; D005072:Evoked Potentials, Auditory / Q000235:genetics / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D010641:Phenotype; D013216:Reflex, Startle / Q000235:genetics / Q000502:physiology*; D012438:Saccades / Q000235:genetics / Q000502:physiology*; D012559:Schizophrenia / Q000175:diagnosis / Q000235:genetics / Q000503:physiopathology; D012569:Schizotypal Personality Disorder / Q000175:diagnosis* / Q000235:genetics* / Q000503:physiopathology