Performance of patients with schizophrenia (n = 15) was compared to that of patients with vascular ischemic lesions of the dorsolateral prefrontal cortex (n= 10) and to age-matched controls (n= 15) in delayed reaction tasks known to be specific markers of the functions of the frontal lobe. The performance of patients with schizophrenia was similar to that of patients with prefrontal lesions in the delayed response task (DR) and the spatial discrimination-reversal task (SD and RV) but not in the delayed alternation task (DA) in which they performed as well as controls. The behavioural profile of responses in delayed reaction tasks for the schizophrenic patients was identical to that of patients with basal ganglia lesions reported in a previous study. These results suggest that in some patients with schizophrenia, a frontal lobe deficit could be indirectly induced by a dysfunction of the basal ganglia. This problem could be due either to the pathological process itself or to the effect of the neuroleptic treatment.
