title: A stratified model for psychosis prediction in clinical practice.
abstract: OBJECTIVE
  Impaired cognition is an important dimension in psychosis and its at-risk states. Research on the value of impaired cognition for psychosis prediction in at-risk samples, however, mainly relies on study-specific sample means of neurocognitive tests, which unlike widely available general test norms are difficult to translate into clinical practice. The aim of this study was to explore the combined predictive value of at-risk criteria and neurocognitive deficits according to test norms with a risk stratification approach.
  
  
  METHODS
  Potential predictors of psychosis (neurocognitive deficits and at-risk criteria) over 24 months were investigated in 97 at-risk patients.
  
  
  RESULTS
  The final prediction model included (1) at-risk criteria (attenuated psychotic symptoms plus subjective cognitive disturbances) and (2) a processing speed deficit (digit symbol test). The model was stratified into 4 risk classes with hazard rates between 0.0 (both predictors absent) and 1.29 (both predictors present).
  
  
  CONCLUSIONS
  The combination of a processing speed deficit and at-risk criteria provides an optimized stratified risk assessment. Based on neurocognitive test norms, the validity of our proposed 3 risk classes could easily be examined in independent at-risk samples and, pending positive validation results, our approach could easily be applied in clinical practice in the future.
authors.affiliation: University Hospital of Child and Adolescent Psychiatry and Psychotherapy, University of Bern, Bern, Switzerland; Shared first authorship chantal.michel@kjp.unibe.ch.
authors.forename: Chantal
authors.initials: C
authors.lastname: Michel
authors.affiliation: Department of Psychiatry and Psychotherapy, University of Cologne, Cologne, Germany Shared first authorship.
authors.forename: Stephan
authors.initials: S
authors.lastname: Ruhrmann
authors.affiliation: University Hospital of Child and Adolescent Psychiatry and Psychotherapy, University of Bern, Bern, Switzerland;
authors.forename: Benno G
authors.initials: BG
authors.lastname: Schimmelmann
authors.affiliation: Department of Psychiatry and Psychotherapy, University of Cologne, Cologne, Germany.
authors.forename: Joachim
authors.initials: J
authors.lastname: Klosterkötter
authors.affiliation: University Hospital of Child and Adolescent Psychiatry and Psychotherapy, University of Bern, Bern, Switzerland;
authors.forename: Frauke
authors.initials: F
authors.lastname: Schultze-Lutter
mesh_terms: D000293:Adolescent; D000328:Adult; D003072:Cognition Disorders / Q000175:diagnosis* / Q000209:etiology; D005500:Follow-Up Studies; D006801:Humans; D009483:Neuropsychological Tests / Q000706:statistics & numerical data*; D011379:Prognosis; D011618:Psychotic Disorders / Q000150:complications / Q000175:diagnosis*; D018570:Risk Assessment; D055815:Young Adult
keywords: at-risk criteria; neurocognition; prediction; processing speed; psychosis; risk estimation