Is tardive dyskinesia a unique disorder?

The role of neuroleptics in causing the tardive dyskinesia syndrome is controversial. To properly assess the contribution of drugs as the etiology of dyskinesias, the effects of aging, the natural history of psychosis, and characteristics of spontaneous dyskinesias must be considered. Though the buccolinguo-masticatory triad is seen more often in tardive than in spontaneous dyskinesias, these two disorders have many symptoms in common. Other dyskinesias, such as idiopathic and tardive dystonia or tardive Tourette's syndrome and dyskinesias in untreated schizophrenia, are poorly understood. Chronic neuroleptic treatment may only precipitate TD in those already predisposed to develop such movement disorders. Tardive dyskinesia is not a unique movement disorder, but rather spans several clinical and epidemiological phenomena which must be considered in a balanced evaluation of how much of the permanent dyskinesias should be attributed to neuroleptic drugs.