Objective: Tardive dyskinesia is a serious and common complication of neuroleptic treatment. Olanzapine is a novel antipsychotic agent exhibiting regional mesolimbic dopaminergic selectivity and a broad-based pharmacology encompassing serotonin, dopamine, muscarinic, and adrenergic receptor binding affinities. The authors’ goal was to compare the incidence of tardive dyskinesia among patients receiving olanzapine and those receiving the conventional dopamine 2 antagonist haloperidol. Method: Data were analyzed from three actively controlled and blind long-term responder studies of subjects meeting DSM-III-R criteria for schizophrenia, schizophreniform disorder, or schizoaffective disorder treated with olanzapine (N=707, up to 20 mg/day, 237 median days of exposure) or haloperidol (N=197, up to 20 mg/day, 203 median days of exposure) who did not have evidence of tardive dyskinesia at baseline. All of the subjects had a chronic disease course (mean greater than 10 years), and there were no significant between-treatment group differences in demographic or disease characteristics. The Abnormal Involuntary Movement Scale and research diagnostic criteria for tardive dyskinesia were used to define the comparative incidence rates of long-term treatmentemergent tardive dyskinesia. Results: The incidence of newly emergent tardive dyskinesia at any visit after baseline, at the final visit, and at the final two clinical assessments was statistically significantly lower among olanzapine-treated patients than among haloperidol-treated patients. Conclusions: These findings support an atypical extrapyramidal symptom profile and the potential of a significantly lower risk of tardive dyskinesia with olanzapine than with haloperidol among patients requiring maintenance antipsychotic treatment. (Am J Psychiatry 1997; 154:1248‐1254)

https://ajp.psychiatryonline.org/doi/pdfplus/10.1176/ajp.154.9.1248

Blind, controlled, long-term study of the comparative incidence of treatment-emergent tardive dyskinesia with olanzapine or haloperidol.

Loss of striatal cholinergic neurons as a basis for tardive and L-dopa-induced dyskinesias, neuroleptic-induced supersensitivity psychosis and refractory schizophrenia

It has been 50 years since the first patients with tardive dyskinesia (TD) were described, but the pathophysiology is only partially understood and effective treatments have remained elusive Newer atypical antipsychotics with less nonspecific activity at dopamine receptors have not heralded the end of tardive dyskinesia and merely highlight the incomplete understanding of the disorder We present an overview of the existing pathophysiology of the disorder and incorporate recent developments in genetics and the study of human synaptic plasticity in other hyperkinetic movement disorders We propose a hypothesis that dopamine-receptor sensitization and altered function of the N-methyl-D-aspartate receptor produces maladaptive synaptic plasticity, which allows the encoding of abnormal motor programs, and propose studies that would falsify or support this hypothesis In conclusion, a maladaptive synaptic plasticity" hypothesis goes some way toward filling in the gaps of existing theories of TD with the pathophysiology of other hyperkinetic movement disorders © 2012 Movement Disorder Society

Tardive dyskinesia is caused by maladaptive synaptic plasticity: a hypothesis.

The vacuous chewing movement (VCM) model of tardive dyskinesia revisited: is there a relationship to dopamine D2 receptor occupancy?

Acute administration of haloperidol induces apoptosis of neurones in the striatum and substantia nigra in the rat.

Dopamine D2 receptor binding characteristics were studied by positron emission tomography (PET) using N-11C-methyl spiperone as receptor ligand in patients on longterm treatment with neuroleptic drugs and in control subjects. Eight of the patients had symptoms of tardive dyskinesia whereas three patients did not have any symptoms. Control subjects comprised 5 healthy volunteers and 7 patients with pituitary tumors. All patients had been free of neuroleptic drugs for at least 4 weeks. The time dependent regional radioactivity in the striatum was measured and the receptor binding rate, k3, proportional to receptor number, Bmax and association rate for the receptor was calculated in relation to the cerebellum. The lack in difference in k3 values between TD patients, neuroleptic treated patients without TD and control subjects throws doubt on the hypothesis that changes in striatal D2 dopamin receptor number or binding affinity is an etiological mechanism for persistent TD.

Striatal binding of 11C-NMSP studied with positron emission tomography in patients with persistent tardive dyskinesia: no evidence for altered dopamine D2 receptor binding.

S. Å. Eckernäs

Papers

Striatal binding of 11C-NMSP studied with positron emission tomography in patients with persistent tardive dyskinesia: no evidence for altered dopamine D2 receptor binding.