The metyrapone test, a useful and reliable procedure for assessing hypothalamic-pituitary-adrenocortical (HPA) axis function, was applied to schizophrenic patients and healthy controls. 4 out of 18 patients had subnormal responses to metyrapone whereas there were no such cases in the 22 control subjects. 1 schizophrenic patient and 3 control subjects had high normal responses to metyrapone. The relationship with the dexamethasone suppression test was found to be complex. These preliminary results suggest that the HPA axis activity patterns in psychiatric illness may be more complicated than previously reported.