Verbal fluency in patients with schizophrenia and affective psychoses and their first-degree relatives

Background. Schizophrenic patients are known to have neuropsychological def icits including impaired verbal fluency, but it is not clear whether this l atter deficit is: (a) a consequence of overall intellectual deficit; (b) sh ared with affective psychotic patients; or (c) shared by the relatives of s chizophrenic patients; and (d) shared by the relatives of affective psychot ic patients. Methods. We administered Thurstone's Verbal Fluency Test to 45 schizophreni c patients and 72 of their relatives, and 30 affective psychotic patients a nd 53 of their relatives. Subjects were asked to generate as many words as possible beginning with the letters 'C' and 'S' and the total was taken as the dependent variable. Subjects also completed the National Adult Reading Test (NART) to provide a measure of (pre-morbid) IQ. Results. Schizophrenic patients generated significantly fewer words than af fective psychotic patients, however adjusting for NART this became non-sign ificant. Schizophrenic (but not affective psychotic) patients generated sig nificantly fewer words than their relatives; again adjusting for NART this became non-significant. Patients who had been exposed to obstetric complica tions (OC +) and those who had not (OC -) had similarly poor verbal fluency scores. Relatives of OC + schizophrenic patients had superior verbal fluen cy than relatives of OC - schizophrenic patients and this remained signific ant after adjustment for NART. Conclusions. The results suggest that some families transmit impairment in verbal fluency as part of a pattern of lower overall IQ. However, in other families, relatives show largely normal neuropsychological function, and th e poorer verbal performance of the schizophrenic member appears to have ari sen secondary to his/her exposure to OCs.