Abstract Thirty-two schizophrenic patients were studied during various phases of the illness. Measurements included (1) urinary excretion rates of several metabolically important substances, including hormones of the adrenal cortex and medulla; (2) blood cell counts and plasma concentrations of substances related to the stress response; (3) vital signs; (4) nutritional intake; and (5) physical activity. Chemical and physiological indicators of the stress response were found to be present only when the patient was hyperactive in addition to his psychotic mental status.