Saccadic system functioning among schizophrenia patients and their first-degree biological relatives.

In Study 1, 30 schizophrenia Ss and 27 nonpsychiatric comparison Ss were presented with a fixation task, a visually guided reflexive saccade (prosaccade) task, a predictive tracking task (0.4-Hz square wave), and an antisaccade task. The 2 groups did not differ on either the fixation or prosaccade tasks. Schizophrenia Ss had an increased number of errors on the antisaccade task and had decreased rightward visually guided saccade amplitudes during the predictive tracking task. In Study 2, 13 psychiatric comparison Ss and 32 first-degree biological relatives of the schizophrenia Ss were compared with the schizophrenia Ss and a larger and older sample of nonpsychiatric Ss (n = 33) on the predictive tracking and antisaccade tasks. The groups did not differ on predictive saccadic tracking. The schizophrenia Ss and their first-degree biological relatives made more errors on the antisaccade task than both the nonpsychiatric and psychiatric comparison groups (who did not significantly differ). Results are consistent with the notion that dysfunction of dorsolateral prefrontal cortex, caudate nucleus, or both is related to liability for schizophrenia.