Note: See also the page on Fibromyalgia. Many patients with ME/CFS also have Fibromyalgia.

Myalgic Encephalomyelitis

The name was created after an epidemic at the Royal Free hospital in London, England in 1955. "My" refers to muscle and "algic" to pain. "Encephalo" refers to brain, "myel" to spinal cord and "itis" denotes inflammation.

Myalgic Encephalomyelitis is used in several countries and shortened to M.E. The name is preferred by many in the patient community. It is listed by the World Health Organization as a disease of the central nervous system.

Chronic Fatigue Syndrome

An epidemic in the mid 1980s was brought to the attention of the U.S. Center for Disease Control. Investigators from the CDC labelled the illness Chronic Fatigue Syndrome and created the first working case definition for CFS in 1988.

The name Chronic Fatigue Syndrome has created a disservice to patients over the years. It trivializes the illness while focusing on one symptom. It has contributed to stigma. Some in the medical community have even dismissed it as not a real illness.

ME/CFS

In 2003, with several names and definitions existing at the time, the international consensus panel chose to use the name ME/CFS to encompass both Myalgic Encephalomyelitis and Chronic Fatigue Syndrome.

SEID

In 2015, the U.S. Institute of Medicine proposed a new definition and the name Systemic Exertion Intolerance Disease. The name highlights the systemic nature, captures the post exertion relapse and defines it as a disease rather than a syndrome. However, without context, the name still provokes a negative attitude and adds to the stigma.

On this site we use the name ME/CFS as it is the name used in the Canadian Consensus Criteria (CCC).