Horizontal and vertical pursuit eye movements, the oculocephalic reflex, and the functional psychoses

Sixteen schizophrenic patients, 16 manic-depressive patients, and 14 nonpatient control subjects were tested for horizontal and vertical smooth pursuit eye movements (SPEM) and the oculocephalic reflex. All patients with impaired horizontal pursuit also displayed disrupted vertical pursuit, suggesting that a common mechanism underlies these abnormalities. The oculocephalic reflex was intact in 96% of the subjects whether or not pursuit was disrupted, suggesting that the locus of the eye movement disorder in psychosis may be cortical. For horizontal pursuit, there were significant differences between schizophrenics and nonpatient controls, and between manic depressives and nonpatient controls, but not between schizophrenics and manic depressives, suggesting that the SPEM disruption occurs with significant prevalence in major functional psychoses and not only in schizophrenia.