Clozapine-Induced Rabbit Syndrome

Sir: The rabbit syndrome is a distinct antipsychotic-induced extrapyramidal syndrome, described by Villeneuve as the rapid, rhythmic involuntary movements of the oral and masticatory muscles except for the tongue, with a frequency of about 5.0 Hz. It is often misdiagnosed as tardive dyskinesia because it appears late in antipsychotic therapy and involves the buccalmasticatory muscle group.