Background: The symptoms of burnout are similar to those of depression on the one hand and chronic fatigue syndrome on the other hand. However, the neuro-endocrine correlates of these two syndromes are the opposite, the former being a hyperfunction of the hypothalamic-hypophysial-cortical axis (HPA) and the latter being a hypofunction of the hpa-axis.
Aim: To find out, via a systematic review of the literature, whether burnout is associated with either a hyperfunction or a hypofunction of the HPA-axis.
Method: We searched PubMed using the following search terms: 'burnout syndrome and burnout', 'adrenocorticotropic hormone', 'corticotropin releasing factor', 'hypothalamic pituitary adrenal axis' and 'cortisol'. We retrieved 16 original articles en one meta-analysis were included in the study.
Results: Functional stress testing showed hypersuppression of the HPA-axis after dexamethasone. Basal cortisol values were found to be less conclusive, although a meta-analysis pointed to a negative association between burnout and cortisol. We did not find any studies that were carried out with the help of physiological, physical or psychological stress factors in burnout.
Conclusion: Burnout is associated primarily with a hypofunction of the HPA-axis, which is a neuro-endocrine characteristic of exhaustion, rather than of depression. However, further studies involving functional stress testing are needed in order to map the neuro-endocrine profile fully and to clarify the link with the deregulation of the immune system.