Relations between cognitive and symptom profile heterogeneity in schizophrenia.

Although numerous studies have consistently revealed cognitive heterogeneity in schizophrenia, the relationships between such heterogeneity and clinical phenomenology are not clear. Clusters derived from cognitive heterogeneity studies may or may not be associated with symptom profile or severity of illness. The purpose of this study was to examine the relationship between cognitive heterogeneity and demographic and clinical phenomenological measures. We examined cognitive heterogeneity in schizophrenia by empirically deriving clusters of patients based upon WAIS-R subtest scores and then analyzed the way in which these clusters related to demographic and symptom variables and to DSM-III-R diagnostic subtypes. Four cognitive clusters were identified that were consistent with previous research. These clusters were differentiated on the basis of educational level and occupational status but not on the basis of symptom profile, severity, or DSM-III-R subtypes. Results suggest that cognitive measures are independent of severity of the disorder and phenomenological symptom presentation in these subgroups of schizophrenic patients.