Scott, L V, Dinan, T G · Journal of affective disorders · 1998 · DOI
This study measured a stress hormone called cortisol in urine samples from people with ME/CFS, people with depression, and healthy individuals. The researchers found that people with ME/CFS had lower cortisol levels than healthy people, while people with depression had higher levels. This suggests that ME/CFS and depression affect the body's stress response system in opposite ways.
This study provides biological evidence that ME/CFS involves a different mechanism than depression, despite overlapping symptoms like fatigue and low mood. Understanding that ME/CFS involves HPA axis hypoactivity (low cortisol) rather than hyperactivity may help guide more targeted treatment approaches and validates ME/CFS as a distinct condition from depression.
This study does not prove that low cortisol causes ME/CFS symptoms, only that an association exists. It cannot explain why the HPA axis becomes underactive in ME/CFS or whether this is a primary cause or secondary consequence of the illness. The small sample size and cross-sectional design limit generalizability and cannot establish causality.
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
Scott, L V & Dinan, T G (1998). Urinary free cortisol excretion in chronic fatigue syndrome, major depression and in healthy volunteers.. Journal of affective disorders. https://doi.org/10.1016/s0165-0327(97)00101-8
BibTeX
@article{mecfsatlas-scott-1998-urinary-free,
author = {Scott, L V and Dinan, T G},
title = {Urinary free cortisol excretion in chronic fatigue syndrome, major depression and in healthy volunteers.},
journal = {Journal of affective disorders},
year = {1998},
doi = {10.1016/s0165-0327(97)00101-8},
note = {PubMed: 9476743},
url = {https://www.mecfsatlas.com/evidence/scott-1998-urinary-free},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-30. https://www.mecfsatlas.com/evidence/scott-1998-urinary-free
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