title: Psychosis prediction: stratification of risk estimation with information-processing and premorbid functioning variables.
abstract: BACKGROUND
  The period preceding the first psychotic episode is regarded as a promising period for intervention. We aimed to develop an optimized prediction model of a first psychosis, considering different sources of information. The outcome of this model may be used for individualized risk estimation.
  
  
  METHODS
  Sixty-one subjects clinically at high risk (CHR), participating in the Dutch Prediction of Psychosis Study, were assessed at baseline with instruments yielding data on neuropsychology, symptomatology, environmental factors, premorbid adjustment, and neurophysiology. The follow-up period was 36 months.
  
  
  RESULTS
  At 36 months, 18 participants (29.5%) had made a transition to psychosis. Premorbid adjustment (P = .001, hazard ratio [HR] = 2.13, 95% CI = 1.39/3.28) and parietal P300 amplitude (P = .004, HR = 1.27, 95% CI = 1.08/1.45) remained as predictors in the Cox proportional hazard model. The resulting prognostic score (PS) showed a sensitivity of 88.9% and a specificity of 82.5%. The area under the curve of the PS was 0.91 (95% CI = 0.83-0.98, cross-validation: 0.86), indicating an outstanding ability of the model to discriminate between transition and nontransition. The PS was further stratified into 3 risk classes establishing a prognostic index. In the class with the worst social-personal adjustment and lowest P300 amplitudes, 74% of the subjects made a transition to psychosis. Furthermore, transition emerged on average more than 17 months earlier than in the lowest risk class.
  
  
  CONCLUSIONS
  Our results suggest that predicting a first psychotic episode in CHR subjects could be improved with a model including premorbid adjustment and information-processing variables in a multistep algorithm combining risk detection and stratification.
authors.affiliation: Department of Psychiatry, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands; Joint first authorship. d.h.nieman@amc.uva.nl.
authors.forename: Dorien H
authors.initials: DH
authors.lastname: Nieman
authors.affiliation: Department of Psychiatry and Psychotherapy, University of Cologne, Cologne, Germany; Joint first authorship.
authors.forename: Stephan
authors.initials: S
authors.lastname: Ruhrmann
authors.affiliation: Department of Psychiatry, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands;
authors.forename: Sara
authors.initials: S
authors.lastname: Dragt
authors.affiliation: Department of Psychiatry, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands;
authors.forename: Francesca
authors.initials: F
authors.lastname: Soen
authors.affiliation: Department of Psychiatry, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands; Department of Neurology and Clinical Neurophysiology, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands;
authors.forename: Mirjam J
authors.initials: MJ
authors.lastname: van Tricht
authors.affiliation: Department of Neurology and Clinical Neurophysiology, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands;
authors.forename: Johannes H T M
authors.initials: JH
authors.lastname: Koelman
authors.affiliation: Department of Neurology and Clinical Neurophysiology, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands;
authors.forename: Lo J
authors.initials: LJ
authors.lastname: Bour
authors.affiliation: Department of Psychiatry, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands;
authors.forename: Eva
authors.initials: E
authors.lastname: Velthorst
authors.affiliation: Department of Psychiatry, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands;
authors.forename: Hiske E
authors.initials: HE
authors.lastname: Becker
authors.affiliation: Department of Psychiatry, Sheba Medical Center, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Mark
authors.initials: M
authors.lastname: Weiser
authors.affiliation: Department of Psychiatry, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands;
authors.forename: Don H
authors.initials: DH
authors.lastname: Linszen
authors.affiliation: Department of Psychiatry, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands;
authors.forename: Lieuwe
authors.initials: L
authors.lastname: de Haan
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D018450:Disease Progression; D018913:Event-Related Potentials, P300 / Q000502:physiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D062706:Prodromal Symptoms; D011379:Prognosis; D016016:Proportional Hazards Models; D011618:Psychotic Disorders / Q000175:diagnosis*; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012917:Social Adjustment; D055815:Young Adult
keywords: P300 event-related potential; clinical high risk; premorbid adjustment; prognostic index; psychosis prediction