Although elevated serum levels of antibodies to the nicotinic acetylch
oline receptor (nAChR) have been reported in neuroleptic treated patie
nts with tardive dyskinesia, such antibodies have not been determined
in comparable nondyskinetic patients. Using a toxin-binding inhibition
assay, we examined serum anti-nAChR antibody levels in 17 DSM-III-R c
hronic schizophrenic patients, seven of whom had persistent tardive dy
skinesia, and 10 normal controls. On the average, anti-nAChR antibody
levels were significantly higher in schizophrenic patients than in nor
mal controls, but did not differ between patients with and without tar
dive dyskinesia, and was not related to age, sex, or duration of illne
ss in patients.