The effect of neuroleptics and tardive dyskinesia on smooth-pursuit eye movement in chronic schizophrenics.

We sought to determine whether such state-related factors as neuroleptic treatment and facio-oral tardive dyskinesia (TD) influence smooth-pursuit eye movement (SPEM) in chronic schizophrenics. The design involved 100 schizophrenics, 64 of whom showed "abnormal" eye tracking. Experimentally drug-withdrawn patients, some of whom were clinically relapsed, were compared with control patients who continued taking medication in prewithdrawal and postwithdrawal SPEM tests. All groups showed a slight worsening in eye-tracking performance on two postwithdrawal tests, but significant group-by-test session "interactions" were not demonstrable. We also determined that patients with TD tend to substitute large, nontracking saccades for SPEM to a significantly greater extent than nondyskinetic patients. Our findings strengthen the supposition that impaired SPEM is a trait in many schizophrenics but suggest that patients with TD be excluded in future studies of SPEM addressed to trait issues.