Tardive dyskinesia, described for the first time in 1957, have increased in frequency since neuroleptics started to be widely used. Is that disorder drug induced, or related to the psychosis, or does it exist in the general population, caused by others factors? This study is a trial in the approach of the problem.
Methodology: the occurrence of tardive dyskinesia was rated for three kinds of populations which are schizophrenics never treated by neuroleptics; schizophrenics under treatment by neuroleptics; general population non psychotic and never treated by neuroleptics. Diagnostic criteria of schizophrenia are DSM III ones. Abnormal Involuntary Movement Scales of NIMH have been used in this work. The percentage is 14% in schizophrenics already treated by neuroleptics, and no one in the other two groups had dyskinesia. The middle duration of the illness in the schizophrenics group was about 12 months. Those results allow us to eliminate possible spontaneous dyskinesia in the general population which is young; to suppose that there is probably no responsibility of the psychosis in this disorder, at least at the beginning of the illness; to confirm that neuroleptic medication, alone or associated with other factors, is responsible for the occurrence of tardive dyskinesia.