Although they are associated with the use of neuroleptics, TD apparently existed before the development of these agents. TDs are most common in patients with schizophrenia, schizoaffective disorder, or bipolar disorder who have been treated with antipsychotic medication for long periods, but they occasionally occur in other patients as well. Some drugs that treat nausea, reflux, and other stomach problems can also cause TD. The following is an typical case report of tardive dyskinesia due to tamoxifen in a neuroleptic-naive breast cancer patient with no history of neurologic and psychiatric problems.