Recent developments in the study of early-onset obsessive-compulsive disorder (OCD) and Tourette's syndrome have implicated an autoimmune etiology in a subset of these conditions, and renewed interest into the possibility of autoimmune pathophysiology underlying other psychiatric disorders. There are several clinical and epidemiologic similarities between autoimmune diseases and schizophrenia: genetic predisposition, but with twin concordance below 50%; waxing and waning course; exacerbation of symptoms or precipitation of relapse by psychosocial stress. However, other mixed evidence has engendered considerable debate in the literature regarding the role of immune mechanisms in schizophrenia. The clinical efficacy and safety of intravenous immunoglobulin (IVIg) in immune-mediated neurological diseases has been documented, and clinical studies of the efficacy of IVIg in the treatment of both Tourette's syndrome and OCD are currently ongoing at the NIMH (see protocol 92-M-0132). In this protocol, we propose a 13-week placebo-controlled double-blind crossover study of IVIg in 25 patients suffering from treatment-refractory childhood-onset schizophrenia. After the first 5 patients have completed the trial, this data will be presented to the NIMH Institutional Review Board and a decision will be made as to whether this trial should proceed.