Tardive dyskinesia in schizophrenics under 60 years of age.

Ninety-one schizophrenics (mean age 34 years) were examined for tardive dyskinesia (TD) during chronic neuroleptic treatment. Dyskinesia was found in 23 (25.3%). The only variable that showed an association with TD was the current doses of neuroleptics: in none of the TD patients did the dose of fluphenazine decanoate (or equivalent) exceed 45 mg/week, whereas it was higher in 23 of the 68 without TD (p less than 0.01). When these 23 "high-dose" patients were disregarded, the TD group differed significantly from the 45 dose-matched non-TD subjects in that it had more common anticholinergic drugs, more common parkinsonian symptoms, and less instances of good remission (p less than 0.05 in each case). There was no association between TD and other considered variables (drug history, age, sex, clinical characteristics, size of the lateral brain ventricles, neurological "soft" signs, cognitive impairment). The results illustrate a relationship between TD prevalence and current doses of neuroleptics and indicate that differences in doses between the groups with and without TD may obscure associations between dyskinesia and other factors.