A comprehensive analysis of verbal fluency deficit in geriatric schizophrenia

Deficits in verbal fluency are common in schizophrenia and may provide keys to some of the abnormalities in the semantic system in schizophrenia. While a number of studies have outlined the severity and implications of verbal fluency deficits in younger schizophrenia patients, these findings have not yet been extended to older patients with schizophrenia. In this study, 392 older (age≥50) patients with schizophrenia were administered phonological and semantic (i.e., category) fluency examinations, as well as tests of learning, memory, language, and praxic skills, and rated for clinical symptoms and functional status. When compared to normative standards, 82% of the patients were impaired in semantic fluency and 83% were impaired in phonological fluency. Both semantic and phonological fluency impairment were significantly correlated with other cognitive variables, total scores on the functional status measure, and with the social and self-care subscales. Scores were uncorrelated with the severity of psychosis, but were correlated with the severity of negative symptoms. Furthermore, the severity of poverty of speech (a clinical measure of verbal underproductivity) was moderate in magnitude and failed to enter as a predictor of verbal fluency, indicating that impaired fluency scores are not simply an artifact of general underproductivity or mutism. The findings support conclusions from studies with younger schizophrenia patients that suggest that verbal fluency impairment is a consequence of a disorganized semantic system. Verbal fluency impairment remains common and functionally relevant in schizophrenia patients in late life.