Temporal stability of smooth-pursuit eye tracking in first-episode psychosis

We evaluated the temporal stability of smooth-pursuit eye tracking in 38 schizophrenic, 42 nonschizophrenic psychotic (bipolar, depressive, paranoid psychotic, and schizophreniform), and 49 normal subjects. Pursuit performance was evaluated on two testing occasions separated by approximately 9.5 months. Retest reliability coefficients of root mean square (RMS) error scores for schizophrenic and normal subjects were .68 and .57, respectively. The reliability coefficients of RMS error scores for the nonschizophrenic psychotic patients ranged from .44 to .51. Level of psychological functioning was not significantly related to tracking performance, and most patients' pursuit performance remained stable despite changes in medication and clinical status. These results support the hypothesis that eye tracking dysfunction is a trait characteristic that can serve as a vulnerability indicator of schizophrenia.