This review article examines what scientists currently understand about how ME/CFS develops and affects the body at a cellular level. Researcher Anthony Komaroff synthesizes evidence suggesting that ME/CFS involves problems with energy production in cells, immune system dysfunction, and nervous system abnormalities. The article helps explain why ME/CFS causes such severe fatigue and why patients often feel worse after physical activity.
Why It Matters
This authoritative review by a leading ME/CFS researcher consolidates evidence showing ME/CFS is a biological illness with measurable pathophysiological abnormalities, not a psychiatric condition. Understanding the biological mechanisms underlying ME/CFS is essential for developing targeted treatments and validating patient experiences.
Observed Findings
Abnormalities in mitochondrial function and cellular energy metabolism in ME/CFS patients
Immune system activation markers and cytokine abnormalities documented in patient populations
Neurological dysfunction including autonomic nervous system dysregulation
Abnormalities in neuroendocrine function, particularly in the HPA axis
Evidence of post-exertional malaise corresponding to metabolic dysfunction
Inferred Conclusions
ME/CFS involves measurable biological abnormalities across multiple physiological systems rather than being primarily psychological in origin
Mitochondrial and metabolic dysfunction appears central to the pathophysiology of ME/CFS
The characteristic post-exertional malaise reflects underlying cellular energy production limitations
Multiple pathophysiological mechanisms likely interact to produce the clinical syndrome
Remaining Questions
What is the primary triggering event or cause that initiates ME/CFS pathophysiology?
How do genetic susceptibility and environmental factors interact to produce ME/CFS?
What This Study Does Not Prove
This review article does not present new experimental data and therefore cannot establish causality—it synthesizes existing findings that may reflect correlation rather than direct cause-and-effect relationships. The article cannot identify which mechanism is primary or which abnormalities are consequences of illness rather than causes. It does not provide definitive proof of any single unified cause of ME/CFS.
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 →