Myalgic Encephalomyelitis, Chronic Fatigue Syndrome, and Chronic Fatigue: Three Distinct Entities Requiring Complete Different Approaches


Purpose of Review

A recent review implicates that myalgic encephalomyelitis (ME), chronic fatigue syndrome (CFS), and chronic fatigue are part of the “fatigue spectrum” and recommends “longitudinal studies integrating biopsychosocial approaches to inform early management and targeted rehabilitation strategies.”

Recent Findings

ME is a neuromuscular disease distinguished by muscle fatigability (prolonged muscle weakness after minor exertion) and specific signs of neurological dysfunction. ME is not equivalent to CFS, as proposed by the authors. CFS is defined as unexplained chronic fatigue accompanied by at least four out of a list of eight specific symptoms. CFS is a distinct clinical entity and not merely a severe variant of CF, as suggested. Proof that CF, CFS, and ME are part of a “fatigue continuum” and that CF can convert to CFS at a later stage is lacking. Biopsychosocial approaches for early management and rehabilitation of CF, as promoted by the authors, are at odds with the current understandings of ME, CFS, and CF. The (bio)psychosocial explanatory models for ME and CFS have proven to be invalid, and the associated interventions, cognitive behavioral therapy and graded exercise therapy, have shown to be ineffective and even potentially harmful.


ME, CFS, and CF are three very distinct clinical entities. Interventions justified by (bio)psychosocial models appear to be unsuccessful and potentially noxious. To develop effective treatments, it is crucial to make a clear distinction between ME, CFS, and CF and to leave the (bio)psychosocial explanations and therapies behind us.

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Correspondence to Frank N. M. Twisk.

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Twisk, F.N.M. Myalgic Encephalomyelitis, Chronic Fatigue Syndrome, and Chronic Fatigue: Three Distinct Entities Requiring Complete Different Approaches. Curr Rheumatol Rep 21, 27 (2019).

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  • Myalgic encephalomyelitis
  • Chronic fatigue syndrome
  • Neuromuscular disease
  • Biopsychosocial
  • Therapies
  • Diagnosis