Growing evidence suggests that autoantibodies to neuronal or endothelial targets in psychiatric disorders exist and may be pathogenic. This review describes and discusses the possible role of autoantibodies related to the psychiatric manifestations in autoimmune diseases, autoantibodies related to the psychiatric disorders present in post-streptococcal diseases, celiac disease, chronic fatigue syndrome and substance abuse, and autoantibodies related to schizophrenia and autism, disorders now considered of autoimmune origin.