Effect of typical antipsychotic medications and clozapine on smooth pursuit performance in patients with schizophrenia.

The effect of typical neuroleptic drugs or clozapine on smooth pursuit eye movements was tested in 13 patients with schizophrenia or schizoaffective disorder with a repeated measures design. Nineteen normal control subjects were also studied. Compared with controls, patients in the unmedicated state had low smooth pursuit gain, had a higher rate of corrective catch-up saccades, and tended to spend less time engaged in the tracking task. The patients did not significantly differ from controls on catch-up saccade amplitude, square wave jerk rate, or anticipatory saccade rate. Medication with clozapine, but not typical neuroleptics, was associated with an increase in median catch-up saccade amplitude. Number of days on clozapine and clozapine dose both correlated significantly with a worsening of oculomotor performance. No effect of medication with typical neuroleptics was found, although there was some evidence suggesting that such an affect may occur after more prolonged treatment.