Plasma cortisol and beta-endorphin immunoreactivity in nonmajor and major depression

Abstract

Plasma cortisol levels of 28 hospitalized patients meeting Research Diagnostic Criteria for major or nonmajor (minor or intermittent) depression were significantly higher than those of 8 normal subjects. Plasma .beta.-endorphin immunoreactivity was significantly lower in patients with nonmajor depression than in those with major depression or in normal subjects. A low ratio of plasma .beta.-endorphin to cortisol immunoreactivity was found to characterize patients in both groups. Through the use of only this ratio, a post-hoc analysis identified 25 depressed patients and 7 controls. These findings have implications for psychiatric diagnosis and the involvement of the endogenous opioid system in the pathogenesis of depression.