title: The Psychosis Continuum: Testing a Bifactor Model of Psychosis in a General Population Sample.
abstract: Although the factor structure of psychosis continues to be debated by taxonomists, recent studies have supported a bifactor model consisting of a general psychosis factor and 5 uncorrelated symptom-specific factors. While this model has received support in clinical samples, it has not been tested at the general population level. Analysis was conducted on Wave 2 of the National Epidemiologic Survey on Alcohol and Related Conditions (N = 34 653). Twenty-two psychotic symptoms were used as observed indicators of psychosis. These items were chosen based on their conceptual similarity to the items used in a similar study based on clinical samples. Confirmatory factor analysis and confirmatory bifactor modeling were used to test a variety of competing models. The best fitting model consisted of a general psychosis factor that was uncorrelated with 5 specific factors: positive, negative, disorganization, mania, and depression. These findings suggest that the bifactor model can be extended to general population samples, supporting the continuity between clinical and subclinical psychotic experiences. Theoretical and practical implications are discussed.
authors.affiliation: School of Psychology, Ulster University, L'Derry, Northern Ireland; m.shevlin@ulster.ac.uk.
authors.forename: Mark
authors.initials: M
authors.lastname: Shevlin
authors.affiliation: School of Psychology, Ulster University, L'Derry, Northern Ireland.
authors.forename: Eoin
authors.initials: E
authors.lastname: McElroy
authors.affiliation: Institute of Psychology, University of Liverpool.
authors.forename: Richard P
authors.initials: RP
authors.lastname: Bentall
authors.affiliation: Health Service and Population Research Department, King's College London.|Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, The Netherlands.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Reininghaus
authors.affiliation: School of Psychology, Ulster University, L'Derry, Northern Ireland.
authors.forename: Jamie
authors.initials: J
authors.lastname: Murphy
mesh_terms: D000293:Adolescent; D000328:Adult; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D008297:Male; D015233:Models, Statistical; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data*; D011618:Psychotic Disorders / Q000145:classification* / Q000503:physiopathology*; D055815:Young Adult