Category fluency performance in patients with schizophrenia and bipolar disorder: The influence of affective categories.

Semantic fluency (SF) and phonological fluency (PF) were examined in large groups of schizophrenia patients, bipolar patients and controls. As well as standard SF categories (animals and food), fluency to two affective categories, happy and fear was measured, i.e. participants were asked to produce as many words as they could that resulted in or are associated with fear or happiness. Schizophrenia patients showed SF and PF deficits. Bipolar patients showed PF deficits. Thus, PF is argued to be a good cognitive marker in both disorders. Severity of delusions was related to SF performance in all patients. The patient groups showed different patterns on the affective categories compared to controls: the bipolar patients were better and produced more words, especially to the happiness category, and the schizophrenia patients were impaired and produced less words. The results suggest an interesting interaction between psychotic illnesses, fluency and emotion.