title: Dimensional psychotic experiences in adolescence: Evidence from a taxometric study of a community-based sample.
abstract: Psychotic experiences of varying severity levels are common in adolescence. It is not known whether beyond a certain severity in the general population, psychotic experiences represent a categorically distinct phenomena to milder psychotic experiences. We employed taxometric analytic procedures to determine whether psychotic experiences in adolescence are taxonic (i.e. categorical) or dimensional. Six different psychotic experiences were assessed in a community sample of approximately 5000 adolescents. Three taxometric procedures were conducted. Across all procedures, there was no evidence of a taxon (i.e. a separate latent population) underlying psychotic experiences in adolescence. Rather, a dimensional structure was supported. The results support the notion that psychotic experiences are continuously distributed throughout the general population, and there is no clear discontinuity between milder and more severe psychotic experiences. Thus, these findings support the use of dimensional approaches to understanding psychotic experiences in etiological studies. In clinical practice, categorical cut-offs are needed: the present findings show that a 'natural' break point is not present for identifying severe psychotic experiences, and it is likely therefore that other criteria (such as general functioning) might better aid decision-making with regards to identifying individuals with severe psychotic experiences in need of care during adolescence.
authors.affiliation: Centre for Brain & Cognitive Development, Department of Psychological Sciences, Birkbeck, University of London, UK. Electronic address: mark.taylor@ki.se.
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Taylor
authors.affiliation: Department of Psychiatry, University of Oxford, UK.
authors.forename: Daniel
authors.initials: D
authors.lastname: Freeman
authors.affiliation: Centre for Brain & Cognitive Development, Department of Psychological Sciences, Birkbeck, University of London, UK. Electronic address: a.ronald@bbk.ac.uk.
authors.forename: Angelica
authors.initials: A
authors.lastname: Ronald
mesh_terms: D000293:Adolescent; D004739:England / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D011618:Psychotic Disorders / Q000145:classification / Q000453:epidemiology / Q000503:physiopathology*; D012720:Severity of Illness Index; D014852:Wales / Q000453:epidemiology
keywords: Adolescence; Psychosis; Taxon