Deficits in the endogenous redirection of covert visual attention in chronic schizophrenia.

In patients with schizophrenia, abnormal performance on the antisaccade task suggests that for overt attentional shifts, there is difficulty with the endogenous modes have opposite goals. We examined whether patients with schizophrenia also have difficulty with the endogenous control of exogenous orienting when endogenous and exogenous control of exogenous orienting for covert shifts of attention. Fifteen medicated patients with chronic schizophrenia and 15 matched controls performed two versions of the covert orienting of attention task (COVAT). On one COVAT, targets appeared at the cued location (TAC) on all trials. On the second COVAT, targets appeared at the contralateral location to the cue (TCC) on all trials. Reaction time (RT) for TAC and TCC trials was equal in the control group. However, for the schizophrenia group, RT for TCC trials was significantly slower than RT for TAC trials. This indicates that patients with schizophrenia were unable to inhibit the orienting of attention to peripheral cues even when they knew that targets would never appear at the same location as the cue. These results suggest that patients with chronic schizophrenia have difficulty utilizing the endogenous strategies to inhibit exogenous covert attentional shifts.