Does night-time cortisol excretion normalize in the long-term course of depression?

Introduction: While there is extensive literature on HPA system activity in acutely depressed patients, there is only limited information about the presence of hypercortisolemia during the interepisode interval of affective disorders. We hypothesized an increase in HPA system activity in depressed patients compared to controls, and proposed that night-time cortisol excretion during follow-up will depend on clinical outcome. Methods: We measured night-time cortisol excretion in 27 patients during an acute episode of major depression as well as a 20-week follow-up. 40 healthy subjects served as control group. Results: During the acute episode depressed patients showed increased levels of night-time cortisol excretion compared to healthy controls. Both, patients with full and sustained remission (n=8) as well as patients with incomplete remission or relapse (n= 19) showed declining cortisol excretion in night-time urine during follow-up. At the end of follow-up cortisol excretion did not differ between patients with affective disorder and healthy controls. Discussion: Irrespective of residual depressive symptoms, HPA system activity declines after the generally investigated acute depressive episode.