title: The dimensionality of schizophrenia concepts in first-episode psychosis.
abstract: This study aimed to determine the dimensionality of concepts of schizophrenia using 11 different diagnostic systems, and then to identify the nature of these dimensions by their relationship to a range of signs and symptoms. The sample consisted of 479 patients admitted with a first episode of functional psychosis. The underlying structure of the 11 diagnostic systems was best represented by an oblique 3-factor solution. Whereas the second and third factors could be meaningfully interpreted by their correlations with signs and symptoms, the first factor, anchored by 'modern' nosologies such as DSM-III-R, was more clearly specified by what it is not (the absence of affective symptoms) rather than by what it is (the presence of characteristic psychotic symptoms). A logistic regression of DSM-III-R diagnosis on to separate diagnostic components supports the contention that duration of illness and affective exclusion criteria discriminate the presence of DSM-III-R schizophrenia much better than the three characteristic psychotic symptom groupings.
authors.affiliation: Department of Psychology, University of Melbourne, Victoria, Australia.
authors.forename: R C
authors.initials: RC
authors.lastname: Bell
authors.forename: P
authors.initials: P
authors.lastname: Dudgeon
authors.forename: P D
authors.initials: PD
authors.lastname: McGorry
authors.forename: H J
authors.initials: HJ
authors.lastname: Jackson
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data; D011594:Psychometrics; D011599:Psychopathology; D011618:Psychotic Disorders / Q000145:classification / Q000175:diagnosis* / Q000523:psychology; D012044:Regression Analysis; D012559:Schizophrenia / Q000145:classification / Q000175:diagnosis*; D012565:Schizophrenic Psychology