Tardive dyskinesia prevalence rates during a ten-year follow-up.

We followed up patients in the State Psychiatric Hospital Mauer-Ohling, Mauer-Ohling, Austria, who had been examined in 1982 to determine the prevalence of tardive dyskinesia (TD). Of the 861 patients examined in 1982, 270 were still in hospital 10 years later. Only these patients were included in our study. The SKAUB (Skala für abnorme unwillkürliche Bewegungen, i.e., The German version of the Abnormal Involuntary Movement Scale) was used to quantify the occurrence of TD. The prevalence rate of TD was 3.7% in 1982 and 12.7% in 1992. The 1992 prevalence rate in patients who had not shown TD symptoms in 1982 was 11.4%. The major risk factor for TD was advanced age.