Clauw, D J · Annals of the New York Academy of Sciences · 2001 · DOI
Many people with ME/CFS, fibromyalgia, and related conditions experience chemical intolerance alongside other symptoms like pain and fatigue. This study reviews research suggesting that these conditions share common biological problems, particularly in how the nervous system processes sensory information—making everyday smells, sounds, or lights feel unusually unpleasant or overwhelming. While stress and worry can sometimes make symptoms worse, the evidence shows that physical changes in the body's sensory processing are doing much of the heavy lifting in causing symptoms.
This study provides a unifying biological framework for understanding why ME/CFS patients often have multiple overlapping symptoms and heightened sensory sensitivity. It validates that nervous system dysfunction—not primarily psychological factors—drives chemical intolerance in most patients, supporting a physiologic rather than psychiatric model of disease.
This review does not prove causation or identify the primary trigger of nervous system dysfunction. It cannot establish the relative contribution of each proposed mechanism in individual patients, nor does it address whether these mechanisms are primary disease features or secondary consequences of another underlying process.
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 →
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