Verbal fluency in schizophrenia: relationship with executive function, semantic memory and clinical alogia

Abstract

To examine whether poor verbal fluency in schizophrenia represents a degraded semantic store or inefficient access to a normal semantic store, 25 normal volunteers and 50 DSM-III-R schizophrenic patients, matched for age, sex and IQ, were recruited. Although schizophrenic patients were impaired on both letter and category fluency, they showed a normal pattern of output in that category was superior to letter fluency, and an improvement in category fluency when a cueing technique was employed (Randolph et al. 1993). These results resemble those found in disorders of frontostriatal systems (Parkinson's and Huntington's disease) and suggest that poor verbal fluency in schizophrenia is because of inefficient access to semantic store. A measure of improvement with cueing was directly related to performance on the Stroop executive task. Of all symptom measures derived from SANS and Manchester Scales, only alogia was related to verbal fluency in that superior improvement correlated inversely with the degree of alogia. It is suggested that both alogia and poor verbal fluency are mediated by the same underlying cognitive abnormality that reflects frontostriatal dysfunction.