De Vries, M, Soetekouw, P M, Van Der Meer, J W et al. · Psychological medicine · 2001 · DOI
Researchers followed Dutch military veterans who served in Cambodia in 1992-1993 and reported fatigue and memory problems after returning home. At 18 months later, about 39% of veterans reported feeling much better or completely recovered, while 57% still had the same symptoms and 4% felt worse. The study found that veterans who started with less severe fatigue and felt they had more control over their symptoms were more likely to improve.
This study provides prognostic data on the natural course of post-deployment fatigue syndromes, identifying factors associated with recovery versus chronic symptom persistence. The finding that perceived control and initial symptom severity predict outcomes has direct relevance to understanding ME/CFS trajectories and informs potential psychological intervention targets for chronically fatigued patients.
This study does not establish causation or mechanism—it describes associations between baseline factors and later outcomes in a specific military population. The findings cannot be directly generalized to ME/CFS patients without validation in that cohort, and the study does not prove that fatigue severity or perceived control *cause* improvement, only that these factors are correlated with it.
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
De Vries, M, Soetekouw, P M, Van Der Meer, J W, & Bleijenberg, G (2001). Natural course of symptoms in Cambodia veterans: a follow-up study.. Psychological medicine. https://doi.org/10.1017/s0033291701003075
BibTeX
@article{mecfsatlas-de-vries-2001-natural-course,
author = {De Vries, M and Soetekouw, P M and Van Der Meer, J W and Bleijenberg, G},
title = {Natural course of symptoms in Cambodia veterans: a follow-up study.},
journal = {Psychological medicine},
year = {2001},
doi = {10.1017/s0033291701003075},
note = {PubMed: 11232919},
url = {https://www.mecfsatlas.com/evidence/de-vries-2001-natural-course},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-27. https://www.mecfsatlas.com/evidence/de-vries-2001-natural-course
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