title: The structure of the extended psychosis phenotype in early adolescence--a cross-sample replication.
abstract: The extended psychosis phenotype, or the expression of nonclinical positive psychotic experiences, is already prevalent in adolescence and has a dose-response risk relationship with later psychotic disorder. In 2 large adolescent general population samples (n = 5422 and n = 2230), prevalence and structure of the extended psychosis phenotype was investigated. Positive psychotic experiences, broadly defined, were reported by the majority of adolescents. Exploratory analysis with Structural Equation Modelling (Exploratory Factor Analysis followed by Confirmatory Factor Analysis [CFA]) in sample 1 suggested that psychotic experiences were best represented by 5 underlying dimensions; CFA in sample 2 provided a replication of this model. Dimensions were labeled Hallucinations, Delusions, Paranoia, Grandiosity, and Paranormal beliefs. Prevalences differed strongly, Hallucinations having the lowest and Paranoia having the highest rates. Girls reported more experiences on all dimensions, except Grandiosity, and from age 12 to 16 years rates increased. Hallucinations, Delusions, and Paranoia, but not Grandiosity and Paranormal beliefs, were associated with distress and general measures of psychopathology. Thus, only some of the dimensions of the extended psychosis phenotype in young people may represent a continuum with more severe psychopathology and predict later psychiatric disorder.
authors.affiliation: Department of Interdisciplinary Social Sciences, University of Utrecht, Heidelberglaan 2, Utrecht, the Netherlands. J.T.W.Wigman@uu.nl
authors.forename: Johanna T W
authors.initials: JT
authors.lastname: Wigman
authors.forename: Wilma A M
authors.initials: WA
authors.lastname: Vollebergh
authors.forename: Quinten A W
authors.initials: QA
authors.lastname: Raaijmakers
authors.forename: Jurjen
authors.initials: J
authors.lastname: Iedema
authors.forename: Saskia
authors.initials: S
authors.lastname: van Dorsselaer
authors.forename: Johan
authors.initials: J
authors.lastname: Ormel
authors.forename: Frank C
authors.initials: FC
authors.lastname: Verhulst
authors.forename: Jim
authors.initials: J
authors.lastname: van Os
mesh_terms: D000293:Adolescent; D000367:Age Factors; D002648:Child; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D015438:Health Behavior; D006306:Health Surveys; D006801:Humans; D008297:Male; D008403:Mass Screening; D008960:Models, Psychological; D009426:Netherlands; D010641:Phenotype; D011446:Prospective Studies; D011618:Psychotic Disorders / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics* / Q000523:psychology; D012307:Risk Factors; D012559:Schizophrenia / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics*; D012565:Schizophrenic Psychology; D012569:Schizotypal Personality Disorder / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics* / Q000523:psychology; D012737:Sex Factors