title: Reduced parietal P300 amplitude is associated with an increased risk for a first psychotic episode.
abstract: BACKGROUND
  P300 abnormalities indicate changes in information processing and are one of the most reliable biological markers of schizophrenia. We sought to investigate whether abnormalities in P300 (P3) or other event-related potentials are also present in subjects at ultra high risk (UHR) for developing psychosis and whether they are helpful in predicting transition to psychosis.
  
  
  METHODS
  The N1, N2, N2b, P2, and P3 amplitudes were assessed in 61 UHR subjects, of whom 18 subjects (30%) made a transition to psychosis over a 3-year follow-up period (UHR + T: age 20.4 years) and 43 (70%) did not (UHR + NT: age 19.3 years), and 28 age- and intelligence-matched healthy control subjects (age 20.0 years). Psychopathology was also assessed.
  
  
  RESULTS
  The UHR + T subjects showed smaller parietal P3 amplitudes, compared with control subjects and UHR + NT subjects. Moreover, the N2b was higher in control subjects compared with both UHR groups. We found no differences in N1 or P2 components between the groups, and our UHR subjects did not exhibit bilateral P3 asymmetry. Reduced P3 amplitudes were the best predictor for subsequent psychosis in the UHR group. The P3 reduction was related to increased social anhedonia and withdrawal and a lower global assessment of social functioning and social personal adjustment.
  
  
  CONCLUSIONS
  The UHR + T subjects showed reduced parietal P3 amplitudes. In addition, a reduced P3 amplitude was the best predictor for subsequent psychosis. If replicated, these findings might contribute to a more accurate prediction of a first psychotic episode. Furthermore, reduced social functioning might be related to information processing deficits in UHR subjects.
authors.affiliation: Department of Psychiatry, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands. m.j.vantricht@amc.uva.nl
authors.forename: Mirjam J
authors.initials: MJ
authors.lastname: van Tricht
authors.forename: Dorien H
authors.initials: DH
authors.lastname: Nieman
authors.forename: Johannes H T M
authors.initials: JH
authors.lastname: Koelman
authors.forename: Johan N
authors.initials: JN
authors.lastname: van der Meer
authors.forename: Lo J
authors.initials: LJ
authors.lastname: Bour
authors.forename: Lieuwe
authors.initials: L
authors.lastname: de Haan
authors.forename: Don H
authors.initials: DH
authors.lastname: Linszen
mesh_terms: D000293:Adolescent; D000328:Adult; D014150:Antipsychotic Agents / Q000627:therapeutic use; D001931:Brain Mapping; D015331:Cohort Studies; D004569:Electroencephalography / Q000379:methods; D018913:Event-Related Potentials, P300 / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D010296:Parietal Lobe / Q000503:physiopathology*; D011569:Psychiatric Status Rating Scales; D011618:Psychotic Disorders / Q000188:drug therapy / Q000401:mortality / Q000473:pathology* / Q000503:physiopathology*; D012307:Risk Factors; D016019:Survival Analysis; D055815:Young Adult
chemical_list: D014150:Antipsychotic Agents