I Terms & Conditions I Security & Privacy I Comments I
Home PageSupportME ShopME/CFS Chat RoomsME/CFS Support GroupsME/CFS NewsletterLibrary of Articles on ME/CFSME/CFS Information Forum
What is ME/CFS?What is ME/CFS?
Definitions of ME/CFSDefinitions of ME/CFS
History of ME/CFSHistory of ME/CFS
How Common is ME/CFS?How Common is it?
What Causes ME/CFS?What Causes ME/CFS?
Other Causes of FatigueOther Causes of Fatigue
Management of ME/CFSManagement
Current Research on ME/CFSCurrent ResearchCurrent Research
Recovery Rates in ME/CFSRecovery Rates
Useful InformationUseful Information


Definitions of ME/CFS

One of the first definitions of ME/CFS originated from the work of Dr. Melvin Ramsay. According to Ramsay's definition, the three principal clinical elements of ME/CFS are:

1) A Unique Form of Muscle Fatiguability: where muscle power can take days to recover; and muscle tenderness together with twitchings or spasms can regularly occur.

2) Circulatory Impairment: encompassing cold extremities, heightened sensitivity to climatic change and excessive sweating.

3) Cerebral Dysfunction: encompassing deterioration in memory and concentration; as well as other cognitive difficulties, sleep disturbances and emotional changes.[1]

New Definitions Emerge

Following such definitions, a number of medical researchers and doctors went on to construct their own definitions of the condition.  Unfortunately, this has inevitably created some degree of confusion as some emphasize particular symptoms and elements differently.  Amongst these include, the U.S. Centre for Disease Control (C.D.C) Criteria devised in 1987[2] (updated in 1994)[3]; the Oxford Criteria[4], developed in 1990 by a group of UK experts; and the Australian group of researchers, led by Professor Lloyd, whose criteria placed extra emphasis on neuropsychological symptoms.[5][6]  Of these, the Centre for Disease Control (CDC) in America is perhaps the most internationally accepted definition.  However, in the opinion of two British doctors, Dr. Ramsay's original work remains the best clinical description to date.[7]

CDC Criteria

Centre for Disease Control (CDC) Criteria

CFS is a syndrome characterised by fatigue that is:

-medically unexplained (i.e. not caused by conditions such as anaemia)

-of new onset (i.e. not lifelong)

-of at least 6 months duration

-not the result of ongoing exertion (e.g. overwork or athletic over-training)

-not substantially relieved by rest

-causing a substantial reduction in previous levels of occupational, educational, social or personal activities.

In addition, there must be four or more of the following symptoms:

-self-reported problems with short-term memory or concentration (cognitive defects)

-sore throats

-tender neck (cervical) or armpit (axillary) glands

-muscle pain (myalgia)

-headaches of a new type, pattern or severity

-unrefreshing sleep

-post-exertional malaise lasting more than 24 hours

-multi-joint pain (arthralgia) without swelling or redness

Conditions which would exclude a diagnosis include:

-established medical disorders known to cause chronic fatigue

-major depressive illness with psychotic or melancholic features (but not anxiety states, somatisation disorder or non-melancholic/psychotic depression)

-any medication which causes fatigue as a side-effect

-eating disorders - anorexia, bulimia or severe obesity

-alcohol or substance abuse

© Copyright Health Resource Ltd. 1999-2000

Disclaimer: SupportME endeavours to provide the best possible service to its users, but cannot accept liability for any loss or damage caused by use of its service. The content is provided for general information only and should not be relied upon for any particular individual or purpose. It is important to always check the current validity of any information with a reliable professional source or with the supplier of the good or service listed. SupportME is not responsible for any diagnosis made by a user developed from the material of the Web site. SupportME is not liable for the contents of any external Web sites listed. The Web site does not recommend or endorse any particular commercial product; nor does any product claim to treat or cure a particular medical condition. Always consult your own GP if you have any worries regarding your health.


[1] Ramsay, M. (1988) ‘Myalgic Encephalomyelitis and Postviral Fatigue States: The Saga of Royal Free Disease’; Shepherd, C. (1999) ‘Living with M.E.’ p.6.

[2] Holmes, G. et al. (1988) ‘ Chronic fatigue syndrome: a working case definition,’ Annals of Internal Medicine, 108, p.387-9.

[3] Fukuda, K. et al. (1994) ‘The chronic fatigue syndrome:  a comprehensive approach to its definition and study,’ Annals of Internal Medicine, 121, p.953-9.  Correspondence: 1995, 123, p.74-6.

[4] Sharpe, M.C. et al. (1991) ‘A report – chronic fatigue syndrome: guide-lines for research,’ Journal of the Royal Society of Medicine,’ 84, p.118-21.

[5] Lloyd, A.R. et al. (1988) ‘What is myalgic encephalomyelitis?’ Lancet, 1, p.1286-7.

[6] Lloyd, A.R.  et al. (1990) ‘Prevalence of chronic fatigue syndrome in an Australian population,’ Medical Journal of Australia, 153, p.522-8.

[7] Shepherd, C. (1999) ‘Living with M.E.’ p.7; Macintyre, A. (1998) ‘M.E./Chronic Fatigue Syndrome: A Practical Guide, p.16.