Sep 16. 1997-- Treatment-emergent tardive dyskinesia occurs
less frequently with olanzapine, an atypical antipsychotic agent, than with
haloperidol, according to an article this month in the American Journal of
Psychiatry.

Researchers at Eli Lilly and Company in Indianapolis, Indiana, led by Dr.
Gary D. Tollefson, compared the incidence of tardive dyskinesia in patients
with schizophrenia, schizophreniform disorder, or schizoaffective disorder
treated with either olanzapine or haloperidol for a median of more than 200
days.

The investigators found that "[t]he incidence of newly emergent tardive
dyskinesia at any visit after baseline...was significantly lower among [the
707] olanzapine-treated patients than among [the 197] haloperidol-treated
patients."

Dr. Tollefson's group calls for further prospective studies with
olanzapine. They comment, "If a favorable difference in treatment-emergent
tardive dyskinesia for olanzapine or another atypical antipsychotic is
confirmed, the clinical impact will be substantial."

Am J Psychiatry 1997:154:1248-1254.

[ I think it is important to note that the patients were "treatment
refractory," which means that they were not responding well to conventional
antipsychotic medications.  Haloperidol (Haldol) is a conventional
antipsychotic medication.  The main point of the article has been made
before:  Clozapine is expensive but it can save costs (to HMOs, insurers,
etc.) by keeping patients well enough that they are not hospitalized.
I guess the important thing about the present study is that it is very
methodologically sound.]