Eye Movement Dysfunctions and Mental Illness
Disorders of smooth pursuit eye movements have been reported in many patients with functional psychoses. Between 50% and 85% of hospitalized schizophrenic patients and between 20% and 50% of manic-depressive patients show these disorders. In contrast, the prevalence of pursuit dysfunctions in the normal population is about 8%. Patients with nonpsychotic psychiatric conditions such as personality disorders or serious neurotic conditions show a prevalence of smooth pursuit eye movement dysfunctions that is no higher than that found in the normal population. Although such dysfunctions are typically associated with a variety of neurological syndromes, such as Parkinson’s disease, multiple sclerosis, and those following hemispheric and brain stem lesions, no obvious central nervous system diseases have been reported in association with the functionally psychotic patients who show eye tracking disorders.