Lens changes and ocular disturbances have been reported in conjunction with the use of antipsychotic drugs. We estimated the incidence rate of a clinical diagnosis of cataract in patients with a psychotic disorder, schizophrenia, and compared it with the rate in the general population. Among the schizophrenic patients, we also examined the role of dose and duration of antipsychotic drugs on the risk of cataract development. We followed up two cohorts of patients 30-85 years of age who were included in the United Kingdom General Practice Research Database. Patients in one group had a diagnosis of schizophrenia (N = 4,209). The other group was an age- and sex-matched cohort of 10,000 patients sampled from the source population. The incidence of cataracts was 4.5 per 1,000 person-years among the general population and 3.5 in the schizophrenia population. Overall, antipsychotic drug use was not associated with the occurrence of cataracts. Nevertheless, among long-term users of chlorpromazine at daily doses of 300 mg or greater, and among users of prochlorperazine, the relative risks were 8.8 (95% confidence interval = 3.1-25.1) and 4.0 (95% confidence interval = 0.8-20.7), respectively. There is no indication that schizophrenia per se is associated with an increased risk of developing cataracts.