Deficit of executive functions in schizophrenia: relationship to neurological soft signs and psychopathology.

Cognitive deficits and neurological soft signs (NSS) have frequently been reported in schizophrenic patients and they both appear related to prominent negative symptoms. The aim of the present study was to examine the relationship between deficit of executive functioning, assessed by the Wisconsin Card Sorting Test (WCST), NSS and psychopathological dimensions of schizophrenia in order to address the issue of whether a typology of schizophrenic patients may be identifiable by clinical, neurological and neuropsychological features. A sample of 26 male schizophrenic patients was divided, on the basis of the performance on the WCST, into two subgroups ('good performers' and 'poor performers') that were compared for the prevalence and severity of NSS, assessed by the Neurological Evaluation Scale (NES), and for the psychopathological features, assessed using the Positive and Negative Syndrome Scale (PANSS). To test for between-group differences, ANOVA was conducted. The 'poor performers' group showed greater severity of NSS: significant differences emerged for the NES total score and for the 'sequencing of complex motor acts' score. However, no significant differences between the groups emerged for any PANSS score. These findings seem to indicate that a common neurobiological abnormality could underlie cognitive deficits, especially concerning executive functioning, and subtle neurological abnormalities often present in schizophrenia, but they appear to deny that such dysfunctional correlates of schizophrenia are related to a prominent negative symptomatology.