Common hypotheses may dominate medical opinion: tardive dyskinesia is semi-officially defined as an iatrogenic extrapyramidal disorder caused by long-term administration of antipsychotic drugs. Its prevalence is still increasing, reaching an average of 30% in recent studies. However, the development of these abnormal involuntary movements may be related to neurologic processes inherent in the treated disease and high prevalence figures may be the result of artificial calculations and extremely sensitive criteria. This hypothesis that tardive dyskinesia may be in some part idiopathic is supported by historical descriptions of dyskinesia in schizophrenic patients long before neuroleptics became available and has also emerged in several recent studies, despite concurrent treatment of the patients with neuroleptics. The available data indicate that "mental disease" is by far the most important risk factor for dyskinesia, followed by age, female sex and, ultimately, antipsychotic treatment. Not surprisingly, the disorder often does not respond to neuroleptic withdrawal and may improve slowly despite ongoing treatment to prevent psychotic relapse. In the absence of a generally applicable therapy for the disease processes leading to dyskinesia, the factors that can be controlled (overestimated need for antipsychotics, routine association with anticholinergics, suboptimal psychosocial support) must remain the basis of prevention of "tardive" dyskinesia.