Different neuropsychological studies have consistently found an attention, memory and executive function deficit in schizophrenic patients. The Positive and Negative Syndrome Scale (PANSS) evaluates different clinical aspects of schizophrenia. Factor analyses of this scale suggest the existence of a “cognitive factor”, constituted by several items pertaining to the different subscales. In order to have an acceptable concurrent validity, this “cognitive factor” should correlate with the execution of neuropsychological tasks. Our objective was to study the correlation between the PANSS “cognitive factor” and the execution of neuropsychological tasks evaluating attention, memory and executive functions.
Thirty-five schizophrenic patients were evaluated using the Continuous Performance Test (CPT), the Rey-Osterrieth Complex Figure Test (Rey CFT) and the Wisconsin Card Sorting Test (WCST). Bivariate partial correlation between the neuropsychological variables and the PANSS “cognitive factor” was examined. In order to obtain this cognitive component, and based on previous studies, items P2, N5, PG10 and PG11 were used.
The PANSS “cognitive factor” was significantly correlated to CPT omission errors (r=0.45; p=0.006), Rey CFT recall after 5 minutes (r=-0.34; p=0.049), Rey CFT recall after 30 minutes (r=-0.40; p=0.020), WCST perseverative responses (r=0.36; p=0.035), and WCST perseverative errors (r=0.35; p=0.041).
The existence of significant correlations between the PANSS “cognitive factor” and performance on neuropsychological tasks evaluating attention (CPT), memory (Rey CFT) and executive functions (WCST) supports the concurrent validity of this factor.