Epidemiology of tardive dyskinesia Part I.

We have performed an epidemiological study concerning tardive dyskinesia on a sample of 332 chronic schizophrenic patients (142 males and 190 females, mean age 48.6 years, mean duration of neuroleptic treatment 14.5 years). We could conclude that the age of patients at the time of assessment procedures is the most important variable. The prevalence of tardive dyskinesia was significantly higher in the older population. The significance of an insidious beginning of the illness might be only secondary to the highly significant role of the age. Other factors, such as sex, type of schizophrenia, initial syndrome, present psychic state, organic syndromes and neuroleptic-induced extrapyramidal syndrome, do not seen to play a role in the prevalence of tardive dyskinesia.