Friedberg, F, Dechene, L, McKenzie, M J et al. · Journal of psychosomatic research · 2000 · DOI
This study looked at how ME/CFS symptoms change over time by comparing people who had been ill for 10+ years with those ill for only a few years. Researchers found that people with longer illness duration reported more severe cognitive problems (like memory and concentration issues), while both groups had immune-related symptoms and flu-like symptoms. The study suggests that ME/CFS symptoms may shift and worsen in specific ways as the illness persists.
Understanding how ME/CFS symptoms evolve over years can help patients recognize what to expect and guide clinical monitoring. The finding that cognitive symptoms intensify with illness duration highlights a critical area for research and symptomatic treatment, potentially improving quality of life for long-term patients.
This study does not prove that cognitive deterioration is inevitable or irreversible in ME/CFS, nor does it establish causation between illness duration and symptom worsening—cross-sectional design prevents determination of whether symptoms cause disease persistence or vice versa. The perceived causes endorsed by patients (viral reactivation, immune abnormalities) remain hypothetical and were not verified by objective testing.
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
Friedberg, F, Dechene, L, McKenzie, M J, & Fontanetta, R (2000). Symptom patterns in long-duration chronic fatigue syndrome.. Journal of psychosomatic research. https://doi.org/10.1016/s0022-3999(99)00077-x
BibTeX
@article{mecfsatlas-friedberg-2000-symptom-patterns,
author = {Friedberg, F and Dechene, L and McKenzie, M J and Fontanetta, R},
title = {Symptom patterns in long-duration chronic fatigue syndrome.},
journal = {Journal of psychosomatic research},
year = {2000},
doi = {10.1016/s0022-3999(99)00077-x},
note = {PubMed: 10750631},
url = {https://www.mecfsatlas.com/evidence/friedberg-2000-symptom-patterns},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-30. https://www.mecfsatlas.com/evidence/friedberg-2000-symptom-patterns
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