AUTOIMMUNE-DISEASES IN THE PEDIGREES OF SCHIZOPHRENIC AND CONTROL SUBJECTS

Autoimmune diseases aggregate in individuals and within pedigrees, and it has been postulated that autoimmune mechanisms may account for a p roportion of schizophrenia. Structured questionnaires were used to int erview the mothers of 121 DSM-III-R schizophrenic patients and the mot hers of 116 controls in order to determine the prevalence of schizophr enia and of autoimmune diseases in their pedigrees. Patients with a sc hizophrenic first degree relative were significantly more likely to al so have a parent or sibling with an autoimmune disease (60% vs. 20%, O R=6.1, 95% CI=2.3-16.5, p=0.0003). A significant excess of insulin dep endent diabetes mellitus (IDDM) was present in the parents and sibling s of schizophrenic patients (OR=9.65, 95% CI=1.3-429.2, p=0.009). Thes e findings suggest that autoimmune mechanisms may play a role in the a etiology of schizophrenia, particularly familial schizophrenia. Associ ations have been established between autoimmune diseases and the HLA e ncoding genes of the major histocompatibility complex on chromosome si x, and it may be that some of the genetic liability to schizophrenia i nvolves these genes.