title: Basic self-disturbance predicts psychosis onset in the ultra high risk for psychosis "prodromal" population.
abstract: BACKGROUND
  Phenomenological research indicates that disturbance of the basic sense of self may be a core phenotypic marker of schizophrenia spectrum disorders. Basic self-disturbance refers to a disruption of the sense of ownership of experience and agency of action and is associated with a variety of anomalous subjective experiences. In this study, we investigated the presence of basic self-disturbance in an "ultra high risk" (UHR) for psychosis sample compared with a healthy control sample and whether it predicted transition to psychotic disorder.
  
  
  METHODS
  Forty-nine UHR patients and 52 matched healthy control participants were recruited to the study. Participants were assessed for basic self-disturbance using the Examination of Anomalous Self-Experience (EASE) instrument. UHR participants were followed for a mean of 569 days.
  
  
  RESULTS
  Levels of self-disturbance were significantly higher in the UHR sample compared with the healthy control sample (P < .001). Cox regression indicated that total EASE score significantly predicted time to transition (P < .05) when other significant predictors were controlled for. Exploratory analyses indicated that basic self-disturbance scores were higher in schizophrenia spectrum cases, irrespective of transition to psychosis, than nonschizophrenia spectrum cases.
  
  
  CONCLUSIONS
  The results indicate that identifying basic self-disturbance in the UHR population may provide a means of further "closing in" on individuals truly at high risk of psychotic disorder, particularly of schizophrenia spectrum disorders. This may be of practical value by reducing inclusion of "false positive" cases in UHR samples and of theoretical value by shedding light on core phenotypic features of schizophrenia spectrum pathology.
authors.affiliation: Orygen Youth Health Research Centre, University of Melbourne, 35 Poplar Road (Locked Bag 10), Parkville, Victoria 3052, Australia. nelsonb@unimelb.edu.au
authors.forename: Barnaby
authors.initials: B
authors.lastname: Nelson
authors.forename: Andrew
authors.initials: A
authors.lastname: Thompson
authors.forename: Alison R
authors.initials: AR
authors.lastname: Yung
mesh_terms: D000293:Adolescent; D016022:Case-Control Studies; D018450:Disease Progression; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D062706:Prodromal Symptoms; D011379:Prognosis; D016016:Proportional Hazards Models; D011618:Psychotic Disorders / Q000175:diagnosis / Q000523:psychology; D012044:Regression Analysis; D012559:Schizophrenia / Q000175:diagnosis*; D012565:Schizophrenic Psychology; D012649:Self Concept; D055815:Young Adult