title: Do subthreshold psychotic experiences predict clinical outcomes in unselected non-help-seeking population-based samples? A systematic review and meta-analysis, enriched with new results.
abstract: BACKGROUND
  The base rate of transition from subthreshold psychotic experiences (the exposure) to clinical psychotic disorder (the outcome) in unselected, representative and non-help-seeking population-based samples is unknown.
  
  
  METHODS
  A systematic review and meta-analysis was conducted of representative, longitudinal population-based cohorts with baseline assessment of subthreshold psychotic experiences and follow-up assessment of psychotic and non-psychotic clinical outcomes.
  
  
  RESULTS
  Six cohorts were identified with a 3-24-year follow-up of baseline subthreshold self-reported psychotic experiences. The yearly risk of conversion to a clinical psychotic outcome in exposed individuals (0.56%) was 3.5 times higher than for individuals without psychotic experiences (0.16%) and there was meta-analytic evidence of dose-response with severity/persistence of psychotic experiences. Individual studies also suggest a role for motivational impairment and social dysfunction. The evidence for conversion to non-psychotic outcome was weaker, although findings were similar in direction.
  
  
  CONCLUSIONS
  Subthreshold self-reported psychotic experiences in epidemiological non-help-seeking samples index psychometric risk for psychotic disorder, with strong modifier effects of severity/persistence. These data can serve as the population reference for selected and variable samples of help-seeking individuals at ultra-high risk, for whom much higher transition rates have been indicated.
authors.affiliation: Department of Psychiatry and Psychology, South Limburg Mental Health Research and Teaching Network, EURON, Maastricht University Medical Centre, Maastricht, The Netherlands.
authors.forename: N
authors.initials: N
authors.lastname: Kaymaz
authors.affiliation: Department of Psychiatry and Psychology, South Limburg Mental Health Research and Teaching Network, EURON, Maastricht University Medical Centre, Maastricht, The Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: Drukker
authors.affiliation: Division of Clinical Psychology and Epidemiology, Max Planck Institute of Psychiatry, Munich, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Lieb
authors.affiliation: Division of Clinical Psychology and Epidemiology, Max Planck Institute of Psychiatry, Munich, Germany.
authors.forename: H-U
authors.initials: HU
authors.lastname: Wittchen
authors.affiliation: Department of Psychiatry, Sheba Medical Centre, Tel-Hashomer, Israel.
authors.forename: N
authors.initials: N
authors.lastname: Werbeloff
authors.affiliation: Department of Psychiatry, Sheba Medical Centre, Tel-Hashomer, Israel.
authors.forename: M
authors.initials: M
authors.lastname: Weiser
authors.affiliation: Department of Psychiatry and Psychology, South Limburg Mental Health Research and Teaching Network, EURON, Maastricht University Medical Centre, Maastricht, The Netherlands.
authors.forename: T
authors.initials: T
authors.lastname: Lataster
authors.affiliation: Department of Psychiatry and Psychology, South Limburg Mental Health Research and Teaching Network, EURON, Maastricht University Medical Centre, Maastricht, The Netherlands.
authors.forename: J
authors.initials: J
authors.lastname: van Os
mesh_terms: D018450:Disease Progression; D006801:Humans; D062706:Prodromal Symptoms; D011618:Psychotic Disorders / Q000453:epidemiology*