Jonsjö, Martin A, Åström, Jenny, Jones, Michael P et al. · Brain, behavior, & immunity - health · 2020 · DOI
This study compared how 'sick' people with ME/CFS and chronic pain feel compared to other groups. Researchers found that ME/CFS and chronic pain patients reported feeling as sick as healthy people who were given a bacterial toxin to trigger temporary inflammation. These high levels of sickness feelings were similar across both conditions and higher than what primary care patients reported, suggesting that the persistent sickness sensation in ME/CFS and chronic pain may involve similar biological mechanisms related to inflammation and how the brain processes illness signals.
This research provides objective evidence that the persistent, pervasive sickness sensation experienced by ME/CFS patients is comparable to that induced by acute immune activation, supporting the hypothesis that immune-to-brain signaling and inflammatory pathways may be centrally involved in ME/CFS pathophysiology. Understanding sickness behavior as a core feature rather than secondary consequence could shift clinical approaches to assessment and treatment and validate patients' experiences of illness severity.
This study does not prove that inflammation causes ME/CFS or that sickness behavior is the primary mechanism of disease. The cross-sectional design cannot establish causality or directionality—elevated sickness behavior could result from underlying pathology rather than causing it. The small sample size for ME/CFS (n=38) limits generalizability, and the study cannot identify which specific immune pathways or brain mechanisms drive these feelings in chronic conditions.
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
Jonsjö, Martin A, Åström, Jenny, Jones, Michael P, Karshikoff, Bianka, Lodin, Karin, Holmström, Linda, et al. (2020). Patients with ME/CFS (Myalgic Encephalomyelitis/Chronic Fatigue Syndrome) and chronic pain report similar level of sickness behavior as individuals injected with bacterial endotoxin at peak inflammation.. Brain, behavior, & immunity - health. https://doi.org/10.1016/j.bbih.2019.100028
BibTeX
@article{mecfsatlas-jonsj-2020-patients-cfs,
author = {Jonsjö, Martin A and Åström, Jenny and Jones, Michael P and Karshikoff, Bianka and Lodin, Karin and Holmström, Linda and Agréus, Lars and Wicksell, Rikard K and Axelsson, John and Lekander, Mats and Olsson, Gunnar L and Kemani, Mike and Andreasson, Anna},
title = {Patients with ME/CFS (Myalgic Encephalomyelitis/Chronic Fatigue Syndrome) and chronic pain report similar level of sickness behavior as individuals injected with bacterial endotoxin at peak inflammation.},
journal = {Brain, behavior, & immunity - health},
year = {2020},
doi = {10.1016/j.bbih.2019.100028},
note = {PubMed: 38377418},
url = {https://www.mecfsatlas.com/evidence/jonsj-2020-patients-cfs},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-30. https://www.mecfsatlas.com/evidence/jonsj-2020-patients-cfs
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