SummaryThe serum and CSF of 66 patients with functional psychoses were tested for immunoglobulins and antibodies to measles, HSV-1, CMV, and rubella viruses. Ten surgical and 80 neurological patients were controls. There were no significant findings in the serum, consistent with most previous studies. In the CSF 6 of 17 multiple admission schizophrenic patients had definite elevations of IgG or measles antibody and differed significantly from the surgical controls. Immunologically this group resembled the seriously ill neurological patients. No previous study has been made of immunoglobulins or viral antibodies in the CSF of psychiatric patients. It is concluded that further work is warranted in a search for biological subgroups of schizophrenia.