Le Bon, Olivier, Minner, Pierre, Van Moorsel, Cédric et al. · Psychiatry research · 2003 · DOI
When people with ME/CFS spend a night in a sleep lab, their sleep patterns often change between the first and second night—a phenomenon called the 'first-night effect.' This study found that ME/CFS patients do experience this adaptation effect, where sleep measurements like total sleep time and sleep quality improve on the second night. Understanding this pattern helps doctors interpret sleep test results more accurately.
Sleep disturbance is a cardinal feature of ME/CFS, yet clinical sleep assessments rely on polysomnography data that may be confounded by laboratory adaptation. This study demonstrates that ME/CFS belongs to a class of medical conditions where first-night effects are clinically meaningful, informing best practices for sleep study interpretation and highlighting the need for standardized recording protocols in ME/CFS research.
This study does not establish the cause of sleep dysfunction in ME/CFS, nor does it prove that first-night effects are universal across all ME/CFS patients—the authors explicitly noted the effect was present in some cases but not others. The cross-sectional observational design cannot determine whether the habituation effect reflects true physiology or is purely a laboratory artifact, and the small sample size limits generalizability.
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
Le Bon, Olivier, Minner, Pierre, Van Moorsel, Cédric, Hoffmann, Guy, Gallego, Soledad, Lambrecht, Luc, et al. (2003). First-night effect in the chronic fatigue syndrome.. Psychiatry research. https://doi.org/10.1016/s0165-1781(03)00185-9
BibTeX
@article{mecfsatlas-le-bon-2003-first-night,
author = {Le Bon, Olivier and Minner, Pierre and Van Moorsel, Cédric and Hoffmann, Guy and Gallego, Soledad and Lambrecht, Luc and Pelc, Isidore and Linkowski, Paul},
title = {First-night effect in the chronic fatigue syndrome.},
journal = {Psychiatry research},
year = {2003},
doi = {10.1016/s0165-1781(03)00185-9},
note = {PubMed: 14527650},
url = {https://www.mecfsatlas.com/evidence/le-bon-2003-first-night},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-28. https://www.mecfsatlas.com/evidence/le-bon-2003-first-night
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