Prevalence of Spontaneous Dyskinesia in Schizophrenia

Spontaneous abnormal involuntary movements phenomenologically identical to neuroleptic-inducedtardive dyskinesia have been described in schizophrenia for over a century. Because atpresent nearly all patients with schizophrenia are exposed to neuroleptic medications, informationabout the prevalence of spontaneous dyskinesia is obtained from accounts from the preneurolepticera, evaluations of first-episode patients before neuroleptic treatment, and the identification and assessmentof drug-naive patients in developing countries. In this report, data from 14 studies ofneuroleptic-naive patients with schizophrenia are used to generate age-adjusted estimates of the prevalenceof spontaneous dyskinesia. While the precision of this estimate is limited by the difficulty ofobtaining large, untreated samples, available data suggest a spontaneous dyskinesia rate of approximately4% in first-episode schizophrenic patients, 12% for patients ill several years but below age 30years, 25% for those aged between 30 and 50 years, and 40% for those aged 60 years or older. Relativeto the incidence and accrued prevalence of spontaneous dyskinesia expected during the natural historyof untreated schizophrenia, the cumulative impact of treatment with new neuroleptic agents has yet tobe determined.