Independence of positive and negative symptoms in a population of schizophrenic patients.

Abstract

Numerous recent studies have divided schizophrenic patients into subgroups based on a predominance of positive or negative symptoms. These works often assume that these symptoms are distributed discontinuously or inversely. In the present work, we sought relationships between positive and negative schizophrenic symptoms in a medication-free inpatient population of schizophrenic patients (N = 61). Measures of positive and negative symptoms were derived from clinical ratings using the Brief Psychiatric Rating Scale. No correlations were found between positive and negative symptoms in the entire group, or in subgroups defined by duration of illness or diagnostic subtype. Furthermore, no correlations were found between positive or negative symptoms and age, age at onset of illness, or duration of illness. These data suggest that positive and negative symptoms vary independently among patients; knowledge about the level of positive symptoms provides no predictive information about negative symptoms. In addition, the distribution of patients showed that a large percentage have a mixture of positive and negative symptoms. Accordingly, methodologies that form restrictive subgroups of patients with exclusively positive or negative symptoms may have little generalizability to schizophrenic populations. The results suggest that schizophrenic patients should not be routinely subtyped as predominantly positive or negative.