Neuropsychological correlates of positive vs. negative schizophrenic symptomatology.

This study attempts to further the validity of the subtype hypothesis in schizophrenia by testing the relationship of neuropsychological functions in schizophrenics with predominantly positive vs. negative symptoms. The Brief Psychiatric Rating Scale (BPRS) was used to parse schizophrenics into positive and negative symptom groups, while a neuropsychological test battery was administered to both types of patients. The results indicate that positive schizophrenic symptomatology is related to frontal executive tasks, whereas negative schizophrenic symptomatology is related to mental tracking tasks that require motoric and dexterous manipulation. However, the absence of non-overlapping symptomatic and neuropsychological functioning groups raises the possibility that a three or more factor model may be more reasonable for reflecting the variety of symptom and neuropsychological patterns in patients, rather than the two-type positive vs. negative dichotomy. The results further the hypothesis that schizophrenia is not a single disease entity.