Category fluency in first-episode schizophrenia.

Animal word list generation (ANWLG) was administered to 47 first-episode schizophrenia (FES) participants and 31 controls. Fifty-nine left temporal lobe epilepsy (LTLE) participants were included as a comparison group with known temporal lobe damage and expected semantic deficits. Semantic knowledge was assessed with the Association Index (AI), a measure of the semantic relatedness of all consecutive ANWLG responses. Neuropsychological tests of language and executive functioning were also administered. Results showed that both FES and LTLE groups generated fewer ANWLG responses than controls, but only the LTLE participants obtained a lower AI relative to controls. FES participants did not differ from controls on the AI. FES and LTLE groups produced fewer semantic subcategories (clusters), however, only the LTLE group produced fewer words per subcategory compared to controls (cluster size). FES participants produced a higher rate of perseverative responses compared to the other groups. Finally, correlation analyses showed that for FES participants both executive and language tests significantly correlated with ANWLG total responses, while the correlation between ANWLG and only 1 language test was significant for LTLE participants. Taken together, the results suggest that reduced ANWLG output in FES participants may be best conceptualized as a deficit in the executive component of word list generation (i.e., semantic search/access, response monitoring) or global cognitive impairment.