Five-factor model of schizophrenic psychopathology: how valid is it?

Abstract

Aim of the study was to examine the consistency of the five-factor model of schizophrenic symptoms, assess its validity and evaluate its dimensional factor structure using confirmatory factor (CFA) analysis. A sample of 258 randomly assigned DSM-III R patients with schizophrenic disorders were studied by means of the structured clinical interview for the Greek validated Positive and Negative Syndrome Scale (PANSS) and were rated on its 30 items. Patients' scores were subjected to principal component analysis (PCA) with varimax rotation. Internal consistency for each of the components was determined by the use of Cronbach's alpha. External validity of the model derived was investigated by searching for possible relationships between the components and sociodemographic characteristics with the aid of canonical correlation analysis. Confirmatory factor analysis (CFA) was also performed. Using the scree plot criterion PCA revealed a five-factor model. These factors were interpreted as representing--in a decreasing order of relative importance--the following dimensions of schizophrenic psychopathology: negative, excitement, depression, positive and cognitive impairment. The model was comparable with six previous factor analytic studies. Internal consistency was quite satisfactory whereas external validity was found to be not so powerful. CFA did not show that the proposed model yields an adequate factor structure.