Verbal Fluency in Schizophrenia: Reduction in Semantic Store

Abstract

Objective: This is a study of the word production of patients with schizophrenia using a semantic verbal fluency task to address the unresolved issue of retrieval or storage impairment. Method: Twenty-one patients with schizophrenia and 11 matched healthy subjects performed a semantic verbal fluency task on ‘food’, ‘animal’ and ‘transport’ categories in Cantonese for 3 minutes each on five separate trials. Results: Patients generated significantly fewer numbers of words compared with control on each trial. The estimated lexicon size of the patients was significantly smaller than that of the equivalent group. The amount of shared words and variable words generated in all five trials were reduced in the patient group. Conclusions: Our results suggest that poor verbal fluency in patients with schizophrenia may partly be attributable to reduction in semantic store. The importance of temporal lobe involvement on verbal fluency deficits needs to be emphasised as an integral part of the neurobiological basis of schizophrenia research.