What is ME?

Myalgic Encephalomyelitis (ME), commonly known as Chronic Fatigue Syndrome (CFS) or ME/CFS, is a devastating multi-system disease that causes dysfunction of the neurological, immune, endocrine and energy metabolism systems.

It often follows an infection and leaves 75% of those affected unable to work and 25% homebound are bedridden. An estimated 15-30 million people worldwide have ME.

Myalgic Encephalomyelitis (ME) is a systemic neuroimmune condition characterized by post-exertional malaise (a reduction in functioning and a severe worsening of symptoms after even minimal exertion). It causes dysregulation of  the immune, nervous, and energy metabolism systems. The effects of ME are devastating enough to leave 25% of patients housebound or bedbound.

All people with ME experience a substantial loss of physical or cognitive functioning, but there is a  spectrum of severity. The typical ME patient scores more poorly on quality of life surveys than those with multiple sclerosis, stroke, diabetes, renal failure, lung disease, heart failure, and various cancers. Onset can be either sudden or gradual, and the intensity or frequency of specific symptoms can wax and wane. While symptoms can fluctuate significantly from day-to-day, shifts in overall wellness should be measured in years, not weeks or months.


An estimated 15-30 million people around the world are suffering from ME; at least 1,000,000 Americans, 250,000 British people, 100,000 Australians, and 560,000 Canadians have ME. An estimated 75-85% of them are women and 80-90% of them are undiagnosed.


Common symptoms include:

  • physical or mental fatigue that prevents the patient from engaging in ordinary activities
  • post-exertional malaise (a reduction in functioning and a severe worsening of symptoms after even minimal physical or cognitive exertion)
  • debilitating pain
  • sleep dysfunction
  • cognitive dysfunction
  • neurological impairment
  • sensory sensitivity
  • severe immune dysfunction

While there is no single laboratory test that can diagnose ME, patients have consistent biological abnormalities demonstrated in research settings. Many specialist physicians use these tests to aid in forming a diagnosis, although the diagnosis is at present most frequently made by excluding other conditions that cause similar symptoms and by using one of several diagnostic criteria. Due to lack of education and awareness about ME, many patients are undiagnosed, or misdiagnosed with other conditions.


There is no FDA approved treatment for ME. Because many ME patients’ symptoms vary over time, specialists often suggest treatments that are highly personalized and change treatment protocols frequently.


#MEAction New Patient Support Group

ME/CFS Diagnosis and Management in Young People: A Primer

IACFS/ME Primer for Clinical Practitioners

Institute of Medicine – Beyond Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Redefining an Illness

Myalgic encephalomyelitis: International Consensus Criteria

Canadian Consensus  – A Clinical Case Definition and Guidelines for Medical Practitioners

CDC Website