Predictors of tardive dyskinesia: results of a cross-sectional study in an outpatient population.

A cross-sectional study was conducted to identify predictors of tardive dyskinesia (TD) in a group of 180 psychiatric outpatients maintained on neuroleptic medications. The estimated prevalence of this involuntary movement disorder was 33% in the total study population. Using multiple logistic regression, we found that TD was independently related to five factors: being 55 yr of age and older; being male; using depot (injectable) neuroleptics; having 6 or more years of neuroleptic exposure; and having less than 6 months of psychiatric hospitalization. In addition, the effect of depot medication was much greater in white males than it was in other race-sex groups. We observed no other interaction effects between pairs of predictor variables, nor did we find significant independent effects of race, denture use, DSM III diagnosis, current neuroleptic dose and potency, percent time on neuroleptics, and recent use of antiparkinsonian drugs or lithium. This study is serving as a pilot investigation for a large prospective incidence study that has already begun among patients at risk of developing TD in the same source population.