The Concept of ME/CFS

The concept of ME/CFS (notionally standing for myalgic encephalomyelitis/chronic fatigue syndrome) has evolved over the last twenty years. This review compares it with the historical terms chronic fatigue syndrome, myalgic encephalomyelitis, and also post-viral fatigue syndrome, arguing that ME/CFS is better suited to both clinical and research needs, focusing on a symptom-based syndrome characterized by post-exertional malaise, orthostatic intolerance, and an unpredictable, fluctuating time course, rather than specific physiological markers. The need to dissociate the clinical concept from speculative theories of aetiology is emphasised. The breakdown in effective care, especially for severe cases, is highlighted and suggestions made for re-instituting a physician-led service that might allow both safe care and a clinical base for badly needed research.