Gaab, Jens, Hüster, D, Peisen, R et al. · Psychosomatics · 2003 · DOI
This study tested whether ME/CFS patients have problems with cortisol, a stress hormone made by the adrenal glands. Researchers gave 18 ME/CFS patients and 18 healthy people a hormone called ACTH (in both low and high doses) to stimulate cortisol production. The results showed no difference between the two groups, suggesting that ME/CFS is unlikely caused by faulty adrenal glands.
Many ME/CFS patients and some researchers have hypothesized that low cortisol levels drive symptoms, making this question clinically relevant. This study provides evidence against a primary adrenal dysfunction mechanism, helping refocus research on other potential HPA axis abnormalities or entirely different pathways in ME/CFS pathophysiology.
This study does not rule out HPA axis dysfunction in ME/CFS—it only excludes primary adrenal insufficiency. It does not address whether patients have abnormal cortisol patterns at baseline, abnormal circadian rhythms, or problems at the pituitary or hypothalamic level. Absence of difference in acute ACTH response does not exclude other endocrine or immune mechanisms underlying ME/CFS.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
The first block is for the primary paper and is the citation you should use in research work. The atlas-snapshot line only applies if you are specifically referring to this atlas’s reading of the paper on the date shown.
Primary citation
Gaab, Jens, Hüster, D, Peisen, R, Engert, V, Heitz, V, Schad, T, et al. (2003). Assessment of cortisol response with low-dose and high-dose ACTH in patients with chronic fatigue syndrome and healthy comparison subjects.. Psychosomatics. https://doi.org/10.1176/appi.psy.44.2.113
BibTeX
@article{mecfsatlas-gaab-2003-assessment-cortisol,
author = {Gaab, Jens and Hüster, D and Peisen, R and Engert, V and Heitz, V and Schad, T and Schürmeyer, Th and Ehlert, U},
title = {Assessment of cortisol response with low-dose and high-dose ACTH in patients with chronic fatigue syndrome and healthy comparison subjects.},
journal = {Psychosomatics},
year = {2003},
doi = {10.1176/appi.psy.44.2.113},
note = {PubMed: 12618533},
url = {https://www.mecfsatlas.com/evidence/gaab-2003-assessment-cortisol},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-28. https://www.mecfsatlas.com/evidence/gaab-2003-assessment-cortisol
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