There is a hypothesis that autoimmune abnormalities in neurotransmitter receptors might cause some psychiatric disorders. Using a sensitive radioligand assay, we detected serum autoantibodies to recombinant human muscarinic cholinergic receptor 1 (CHRM1, 34.4%), mu-opioid receptor (OPRM1, 13.1%), 5-hydroxytryptamine receptor 1A (HTR1A, 7.4%), and dopamine receptor D2 (DRD2, 4.9%) in 122 psychiatric patients. Positive antibodies to CHRM1 were found in 34.1%, 34.9%, 33.3%, and 9.1% of patients with schizophrenic disorders (n=44), mood disorders (n=63), other psychiatric disorders (n=15) and autoimmune diseases (n=33), respectively. All three patients with neuroleptic maliganant syndrome had high activities of autoantibodies to CHRM1, OPRM1, and/or HTR1A. Our data suggest that autoimmunity to neurotransmitter receptors might be associated with the induction of psychiatric symptoms and have some relation to neuroleptic malignant syndrome.