Several authors * have reported lower levels of reduced glutathione (GSH) in the blood of patients with endogenous psychosis. Recently, in our search for possible biochemical correlates of schizophrenia, we found evidence that these patients oxidized adrenaline more rapidly than normal persons without systemic disease.† Our data indicated that the increased speed of adrenaline breakdown was not specific for schizophrenia, and we therefore have been searching for a more basic substance which might shed light on this observation. Since lower glutathione levels seem to be a quite consistent finding, we were interested in exploring this phenomenon further to determine if it might be related to our findings with adrenaline metabolism. In the present study, we have compared the glutathione levels of hospitalized schizophrenic patients and outpatient, so-called "pseudoneurotic," schizophrenics with levels obtained from normals and patients without evidence of psychosis, but with a variety of systemic diseases. We compared these findings