Validity of the cognitive factor of the Positive and Negative Syndrome Scale as a measure of cognitive functioning in schizophrenia.

Introduction: The Positive and Negative Syndrome Scale (PANSS) is a widely used instrument for measuring symptomatology in patients with schizophrenia. Numerous studies have analyzed the factorial structure of this scale and have suggested a fivefactor model, namely: negative, positive, excited, anxiety/depression, and disorganized (or cognitive). The latter factor has been related to neuropsychological tests, with a view to analyzing its utility as a measure of cognitive functioning in schizophrenia, but data are inconclusive. The aim of the present study was to analyze the factorial structure of the PANSS and to assess the relationships between factors and neurocognitive tests.
Material and Methods: The sample comprised 235 outpatients diagnosed with schizophrenia. To investigate the factorial structure of the PANSS, a principal component factor analysis was performed. Cognitive functioning was measured with a shortened version of the Barcelona Test.
Results: Unlike previous studies, our study obtained a six-factor model, with disorganized and cognitive symptoms separated in two different factors. The cognitive factor obtained in this study was related to all subtests of the Barcelona Test. The disorganized factor, however, was only related to two of these subtests.
Conclusions: Our results support the use of a six-factor model and suggest that the cognitive factor could be a valid measure of cognitive deficits in schizophrenia, although the use of a standard neuropsychological battery is advisable.
(Copyright © 2009 Sociedad Española de Psiquiatría and Sociedad Española de Psiquiatría Biológica. Published by Elsevier Espana. All rights reserved.)