Involuntary movement disorders were investigated in a psychiatric hospital in Japan. The prevalence of tardive dyskinesia was 9.9% and four clinical variants of tardive dyskinesia could be classified. Of the 716 patients, tardive dystonia was identified in 15 cases, tardive akathisia in one, respiratory dyskinesia in two and rabbit syndrome in 17. The existence of tardive forms for acute dystonic reactions and akathisia suggests that any type of acute extrapyramidal symptoms can have a tardive form.