Jason, Leonard A, Porter, Nicole, Hunnell, Jessica et al. · Rehabilitation psychology · 2011 · DOI
This 10-year study followed 32 people from the community who had been diagnosed with ME/CFS to see how their condition changed over time. Researchers found that most people with ME/CFS remained quite ill, though a few improved or developed other conditions. A key symptom called post-exertional malaise—where physical activity makes symptoms much worse—was the best marker that distinguished people with ME/CFS from others.
This is one of the few long-term studies following ME/CFS patients in community settings rather than clinics, reducing bias from patients who seek treatment. The finding that post-exertional malaise is the most distinctive symptom helps researchers and doctors better identify and understand ME/CFS. Understanding the natural course of the disease over a decade provides patients and clinicians with realistic expectations about prognosis.
This study does not prove what causes ME/CFS or why some people improve while others worsen. The small sample size and loss of participants over 10 years means results may not apply to all ME/CFS patients. Correlation between socio-environmental factors and CFS status does not establish 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
Jason, Leonard A, Porter, Nicole, Hunnell, Jessica, Brown, Abigail, Rademaker, Alfred, & Richman, Judith A (2011). A natural history study of chronic fatigue syndrome.. Rehabilitation psychology. https://doi.org/10.1037/a0022595
BibTeX
@article{mecfsatlas-jason-2011-natural-history,
author = {Jason, Leonard A and Porter, Nicole and Hunnell, Jessica and Brown, Abigail and Rademaker, Alfred and Richman, Judith A},
title = {A natural history study of chronic fatigue syndrome.},
journal = {Rehabilitation psychology},
year = {2011},
doi = {10.1037/a0022595},
note = {PubMed: 21401284},
url = {https://www.mecfsatlas.com/evidence/jason-2011-natural-history},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-30. https://www.mecfsatlas.com/evidence/jason-2011-natural-history
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