The three factors of the psychoticism scale of SCL-90-R

Former studies have repeatedly found the psychoticism (PSY) scale of Symptom Checklist-90-Revised to be a heterogeneous construct. The aim of this study was to confirm and further explore the nature of this heterogeneity within a large sample of patients with mainly personality disorders. Within a total sample of 3 794 patients, one-half was randomly selected for explorative factor analysis in order to assess the internal structure of the PSY scale and the other half to cross-validate the findings by a confirmatory factor analysis. The total sample was then used to assess associations between the components from the factor analyses and several clinical measures and diagnoses. A one-factor solution of the PSY scale yielded poor fit to the data, but a proposed structure of three latent constructs was confirmed by good model fit. The three subsets of the PSY scale, labelled metacognitive dysfunction, self-accusation and detachment, shared variance with different personality disorders and different aspects of psychopathology, e.g. previous psychotic episodes. The heterogeneous PSY scale of SCL-90-R can be divided into three meaningful clinical concepts, reflecting different aspects of psychosis-near experiences. The factors warrant confirmation in other populations. Copyright © 2014 John Wiley & Sons, Ltd.