Neuropsychological Characteristics of Positive and Negative Symptoms of Schizophrenia: Implications for Cognitive Remediation

Abstract

<p>This study examines the relationship between neuropsychological functioning and positive versus negative symptoms of schizophrenia in order to test the hypothesis that negative symptoms are uniquely associated with cognitive deficits and attentional impairment. Forty chronic schizophrenics were subtyped on the basis of symptoms which were predominantly positive (n=10), predominantly negative (n=10), both positive and negative (n=10), or neither positive nor negative (n=10) and administered a battery of neuropsychological tests. The possibility that patterns of deficits among subtypes, if found, reflect lateralized or localized dysfunction was also examined.</p> <p>Test data revealed that positive- and negative-symptom schizophrenics are equally impaired according to several global indices of neuropsychological functioning as well as on various measures of attention. These findings are inconsistant with the hypothesis that cognitive and attentional deficits are unique to negative-symptom schizophrenia as has been reported in the literature. Further analysis of deficit patterns revealed that positive-symptom schizophrenics, relative to the asymptomatic group, showed more marked deficits in verbal learning and memory whereas negative-symptom schizophrenics, based on identical comparisons, showed greater impairment on measures of fluency and productivity. No relation was observed between neuropsychological indicies of right versus left or, anterior versus posterior dysfunction and a patient's symptom status. In fact, the low correlation between psychiatric symptoms and neuropsychological performance was generally observed. Reconceptualization regarding defining characteristics of postive- and negative-symptom syndrome, particularly with respoect to assumptions about attention and cognition, is suggested.</p> <p>The heterogeneity of neuropsychological deficits found among schizophrenics and their dissociation from the patients psychiatric presentation, stress the need for independent, individual assessment of cognitive functioning. Given that neuropsychological deficits, when identified, likely contribute to imparied social and occupational functioning, improvement in neuropsychological status may translate into improvement in these areas of everyday living. Preliminary results of an attempt at computer-based cognitive remediation in a seleted subset of schizophrenics are presented and a neuropsychological approach to psychiatric rehabilitation is proposed.</p>