Olanzapine-induced Concurrent Tardive Dystonia and Tardive Dyskinesia in Schizophrenia with Intellectual Disability: A Case Report

Tardive dystonia and tardive dyskinesia (TDs) are rare extrapyramidal side effects that develop after long-term use of antipsychotics, but they are different syndromes and rarely occur at the same time. Olanzapine is an atypical antipsychotic drug associated with a low risk of extrapyramidal side effects in schizophrenia, but its associations with tardive movements are not clear. We present a case of a 19-year-old Asian female patient with schizophrenia and intellectual disabilities who developed concurrent TDs after long-term use of olanzapine. At her 10-month follow-up examination, her concurrent TDs had been treated successfully with clozapine. This case demonstrates that although the use of olanzapine to treat psychosis and behavioral disturbances is increasing due to its high efficacy and low rate of extrapyramidal side effects, concurrent TDs should be carefully assessed after long-term use of this antipsychotic, especially in patients with schizophrenia and intellectual disabilities. Clozapine, by preventing or reversing the debilitating consequences of concurrent TDs, may be an effective treatment for these patients.