Sharpe, M, Hawton, K, Clements, A et al. · BMJ (Clinical research ed.) · 1997 · DOI
This 1997 study examined whether people with ME/CFS have differences in serotonin activity in their brains. Serotonin is a chemical messenger that affects mood, sleep, and energy. The researchers found that men with ME/CFS showed increased brain serotonin function compared to healthy controls, which was unexpected since low serotonin is often associated with fatigue and depression.
This study challenges the simple assumption that ME/CFS results from low serotonin and suggests the neurobiological picture is more complex. Understanding specific brain chemical abnormalities could help develop targeted treatments and explain why standard antidepressants (which increase serotonin) often do not improve ME/CFS symptoms.
This study does not prove that increased serotonin function causes ME/CFS or that it is the primary mechanism of the illness. It also does not establish whether this finding applies to women with ME/CFS or represents a cause versus a consequence of the disease. Correlation between serotonin activity and ME/CFS status does not indicate causation.
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
Sharpe, M, Hawton, K, Clements, A, & Cowen, P J (1997). Increased brain serotonin function in men with chronic fatigue syndrome.. BMJ (Clinical research ed.). https://doi.org/10.1136/bmj.315.7101.164
BibTeX
@article{mecfsatlas-sharpe-1997-increased-brain,
author = {Sharpe, M and Hawton, K and Clements, A and Cowen, P J},
title = {Increased brain serotonin function in men with chronic fatigue syndrome.},
journal = {BMJ (Clinical research ed.)},
year = {1997},
doi = {10.1136/bmj.315.7101.164},
note = {PubMed: 9251547},
url = {https://www.mecfsatlas.com/evidence/sharpe-1997-increased-brain},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-28. https://www.mecfsatlas.com/evidence/sharpe-1997-increased-brain
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