Combined dexamethasone/CRF test in remitted outpatients with recurrent major depressive disorder.

Background: Hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis is a prominent neurobiological finding during a major depressive episode, reflecting a state dependent factor. An issue under investigation is whether the dysfunction of the HPA axis has also a role to play as a state-independent or trait factor for major depressive disorder (MDD). In relation to this, it is important to examine HPA axis function in patients who are clinically remitted from depression.

Methods: Twenty-three remitted outpatients with recurrent MDD and 23 age- and gender-matched control individuals without a history of MDD participated in the sensitive combined dexamethasone/corticotropin-releasing factor (DEX/CRF) test.

Results: Free salivary cortisol responses were not significantly different between the two groups, although three patients (13%) displayed extremely elevated cortisol responses after CRF.

Limitations: Limited sample size. All but one patient were under treatment with an antidepressant.

Conclusions: This study shows no evidence for a disturbed DEX/CRF test as a state-independent factor in recurrent MDD on a group level. However, MDD is a complex and heterogenic disorder. Probably, there is a subgroup of patients who show a disturbed DEX/CRF test due to an inherited and/or acquired predisposition or as a biological scar after previous depressive episodes.