Earlier studies have examined the symptom dimensions of the PANSS (Positive And Negative Syndrome Scale) in patients with chronic schizophrenia, regardless predominance of symptoms. The aim of this study was to examine the component structure of the PANSS in patients with schizophrenia spectrum disorders and predominantly negative syndrome.

Data of PANSS were extracted from a cross-sectional and retrospective multicenter study in 1,704 adult psychiatric outpatients meeting DSM-IV criteria for schizophrenia, schizophreniform or schizoaffective disorder. We used 5 items of the PANSS negative subscale to individually determine the presence of a negative syndrome when the score on all of the 5-items were >3, with no extrapyramidal symptoms, anxiety, or depression and dose of haloperidol, when applicable, ≤15mg/day. Exploratory factor analysis was carried out using principal component analysis to extract domains. Eigenvalues above 1 according with Kaiser K1 rule were applied to extract factors. Items with a loading of ≥ 0.4 were considered to load on a component.

A total of 307 [61% men, mean age: 41 (SD:12) years] fulfilled criteria for inclusion in the analysis. Principal component analysis of the PANSS revealed four components: positive, negative (all negative items of the original PANSS plus items 15 and 16 of the general psychopathology subscale), mood and disorganization, explained 58% of the total variance. Internal consistency (Cronbach-alpha) of these 4 domains was high: 0.897, 0.874, 0.819 and 0.833, respectively.

This analysis suggest a four component structure of the PANSS in patients with schizophrenia spectrum disorders and predominantly negative syndrome.