Neuropsychological Performance and Positive and Negative Symptoms in Schizophrenia

It has been hypothesized that negative symptom schizophrenia is associated with cognitive dysfunction and that brain impairment may mediate this relationship. The present study examined a variety of cognitive functions in schizophrenics in order to explore the relation between symptoms and performance. A battery of neuropsychological tests was administered to schizophrenics (n = 44), bipolar patients (n = 15), and normal control subjects (n = 12). Group comparisons revealed generalized deficits in schizophrenics. They also showed that positive symptom schizophrenics scored below normal subjects and negative symptom patients on two measures tapping verbal memory. Multiple regression analyses revealed that negative symptom ratings were inversely associated with performance on visual-motor tasks, whereas positive symptoms were inversely associated with verbal memory performance. The findings of this study are not consistent with the notion that cognitive deficits are uniquely associated with negative symptoms. Instead, the results suggest that there may be specific cognitive correlates of both the positive and negative symptom dimensions.