• The US 1994 Fukuda (or CDC) definition of CFS. This definition was created by Keiji Fukuda, Stephen Straus, Ian Hickie, Michael Sharpe, James Dobbins and Anthony Komaroff in the US in 1992, and was revised in 1994. This definition requires that a patient experience new onset of fatigue, plus four or more of the following symptoms; impaired memory or concentration, sore throat, tender cervical or axillary lymph nodes, muscle pain, multi-joint pain, new headaches, unrefreshing sleep or post-exertional malaise. Psychiatric illness is not an exclusion criteria (only major psychiatric illness such as psychotic depression, bipolar disorder and schizophrenia are excluded). It should also be noted that in many recent studies (including the latest CDC CFS research) a modified version of this criteria is being used whereby the condition that a patient have four of the eight symptoms listed is waived and a patient is said to qualify for the diagnosis purely on the presence of the symptom of fatigue.
  
• The UK 1991 Oxford definition of CFS. This definition was created by Michael C. Sharpe, Len Archard, Jangu Banatvala, Simon Wessely, A. David, Peter White et al. in the UK. Fatigue is the only symptom which is essential for the diagnosis of Oxford CFS. The symptom of fatigue was defined by this group as being not organic in origin and as a psychiatric condition - a form of avoidance or symptom of depression. Psychiatric illness is not an exclusion criterion for Oxford CFS.
  
• Australian definitions of CFS - 1988 and 1990. Andrew Lloyd, Denis Wakefield, Clement R. Boughton and John Dwyer in 1988. Andrew Lloyd, Ian Hickie, Clement R. Boughton, Owen Spencer and Denis Wakefield in 1990. The 1988 Australian CFS definition was a definition of post-viral fatigue syndrome or fatigue state caused by viral illnesses including glandular fever, and Q fever. It is described as a state of prolonged fatigue following a viral illness. By definition the condition is self-limiting and the physical effects will be resolved in two years or less. In 1990 the definition of post-viral fatigue was more closely aligned with the psychiatric model of fatigue. To fit this second definition patients must have: 1. Fatigue 2. Impairment of concentration and new onset of short-term memory impairment, and 3. No alternative diagnosis found by history or physical exam over a six-month period. Psychiatric illness is not an exclusion criteria.

None of these CFS definitions is a description of any neurological disease, including Myalgic Encephalomyelitis. M.E. is not defined by ‘fatigue’ is not ‘medically unexplained’ and is certainly not merely a diagnosis of exclusion. M.E. is a distinct organic neurological disease.

The summaries of each of these CFS definitions were taken from the paper ME and CFS, the Definitions produced by the Committee for Justice and Recognition of M.E. For more information on the definitions of M.E. and CFS see this paper, and: The Definitions of M.E. (and CFS) and The Nightingale Definition of M.E.

Post viral fatigue states and fatigue syndromes (eg. following glandular fever/mononucleosis, hepatitis, Ross river virus, flu, Q fever and many other infections)

Symptoms of post-glandular fever/mononucleosis fatigue syndrome include: severe fatigue not satisfied by sleep, recurrent tonsillitis, chronic sore throat and swollen lymph glands in the neck, aches and pains in the limbs, brain ‘fog,’ lack of concentration, depression, deep lethargy, not being able to stand lots of noise, people or strong smells (perfume, cleaning materials etc.), pins and needles, not feeling all there, feelings of having no energy, and various glandular fever/mononucleosis symptoms. (Reference)

Fibromyalgia

The two primary criteria for the classification of Fibromyalgia are: 1) A history of widespread pain involving all four quadrants of the body (right side, left side, above waist, below waist) for a period of at least 3 months. 2) Upon physical examination, the presence of pain in at least 11 of 18 tender points when touched or pressed with force amounting to the equivalent of 4 kg or 9 lbs, although some physicians will diagnose Fibromyalgia without these. (Reference) Other symptoms may include: Tenderness in the neck, shoulder, knee, elbow, or upper buttocks or thigh areas. Trouble sleeping. Tiredness in the morning or late in the day. Mood changes. Headaches. Difficulty concentrating. Numbness and tingling in hands, arms, feet, legs or face. Abdominal pain. Bloating. Constipation. Diarrhea. (Reference)

Candida

Symptoms of systemic fungal infection (candida) include: Allergies to foods and/or airborne chemicals, continual fatigue often more noticeable after eating, poor digestion, constipation, diarrhoea, gas, bloating, cramps, heartburn, sugar craving, irritability, mood swings, headaches, migraine, a ‘fogged in’ feeling, poor concentration, dizziness, depression, anxiety, vaginal infections, menstrual problems, impotence, infertility, prostatitis, rectal itch, urinary infections, catches colds and flu easily, congestion, post nasal drip, asthma, bronchitis, earaches, sore throats, athlete’s foot, jock itch, hives, psoriasis, skin rashes, hyperactivity, feeling bad all over, cold extremities, aches, white coated tongue upon rising. (Reference)

Athletes over training syndrome

Symptoms of athletes over-training syndrome include: a washed-out feeling, tiredness, feeling drained, lack of energy, mild leg soreness, general achiness, pain in muscles and joints, sudden drop in performance, insomnia, headaches, increased number of colds, sore throats, decrease in training capacity or intensity, moodiness, irritability, depression, loss of enthusiasm for the sport, decreased appetite, increased incidence of injuries. (Reference)

Burnout

The symptoms of burnout can include: physical fatigue, frequent illness, sleep problems, disillusionment, the loss of a sense of meaning and cynicism towards others, feelings of helplessness, frustration of efforts and a lack of power to change events, strong feelings of anger against the people we hold responsible for the situation, feelings of depression and isolation, increasing detachment from co-workers, marked reduction in commitment to work, increased alcohol consumption. (Reference)

MCS or MCSS

People with MCS have reported a wide range of symptoms including: headache, fatigue, dizziness, nausea, irritability, confusion, difficulty concentrating, intolerance to heat or cold, earache, stuffy head or congestion, itching, sneezing, sore throat, memory problems, breathing problems, changes in heart rhythm, chest pain, muscle pain and/or stiffness, bloating or gas, diarrhea, skin rash or hives, mood changes. (Reference)

Symptoms of M.S. can include: severe fatigue or lassitude, numbness (and/or tingling) of the face, body, or extremities (arms and legs), feeling of detachment in the body, freezing cold hands and feet, (actual or sensations of), impaired sensations of heat, cold, sudden energy loss that leaves the person dazed and unable to communicate; may fall asleep suddenly, vertigo that may be so severe it can be accompanied by vomiting and nausea and an inability to walk in a straight line, sudden need to urinate, incontinence, urinary retention, pain that varies in type and severity (includes aching joints, burning, shooting, stabbing, cramping, facial nerve pain), weakness in the body (arms, legs feel like lead, sensation of having to drag legs along), lack of co-ordination, lack of balance, walking in a drunken stagger, weakness and paralysis, muscle stiffness, clumsiness, minor and temporary flaring in symptoms (pain, loss of energy) after exercise, tinnitus, hearing impairment (words sound scrambled and non-sensical), blurred double vision, blind spots, colour dimming, partial loss of sight, speech difficulties, slurring, jerky speech, garbled speech, impotence, loss of sexual sensation, emotional lability, short-term memory loss, e.g.going to the wrong place, problems concentrating and reasoning, food allergies, dietary sensitivities. (Reference)

Signs and symptoms of Hypothyroidism include: weak slow heart beat, muscular weakness and constant fatigue, sensitivity to cold, thick puffy skin, slowed mental processes and poor memory, constipation, goitre. Signs and symptoms of Hyperthyroidism include: rapid forceful heartbeat, tremor, muscular weakness, weight loss in spite of increased appetite, restlessness, anxiety and sleeplessness, profuse sweating and heat intolerance, diarrhea, eye changes, goitre. (Reference)

Adrenal insufficiency

Symptoms of adrenal insufficiency include: fatigue and loss of energy, loss of appetite, nausea, vomiting, diarrhea, abdominal pain, weight loss, muscle weakness, dizziness when standing, dehydration, anxiety and depression, increased bronze pigmentation of the skin and mucous membranes and decreased tolerance to cold. Women lose pubic and underarm hair and stop having normal menstrual periods. (Reference)

Early symptoms of cancer can include: chronic fatigue, weakness, dizziness, drowsiness, a change in bowel or bladder habits, loss of feeling in arms or legs or difficulties in walking, a persistent cough or coughing blood, constant indigestion or trouble swallowing; unusual bleeding, paleness; fever and flu-like symptoms, bruising and prolonged bleeding, enlarged lymph nodes, digestive discomfort, discomfort or pain in the abdomen; nausea and vomiting, diarrhea or constipation, bloating after meals, headaches that tend to be worse in the morning and ease during the day, that may be accompanied by nausea or vomiting, pain in bones and joints, frequent infections, changes in personality, memory or speech, weight loss; night sweats (Note that symptoms vary depending on the type of cancer) (Reference)

Brain tumours, including astrocytomas, gliomas

Symptoms of brain tumour can include: fatigue, sluggishness and drowsiness, headache (usually just after waking and lessening as the day goes on), vomiting, uncoordinated clumsy movements, seizures. muscle weakness on one side of the face causing a one-sided smile or drooping eyelid, difficulty with swallowing and with speech, personality changes, weakness, muscle wasting or spasms, and sensory changes (Reference)

Transverse Myelitis

Symptoms of Transverse Myelitis include: limb weakness, sensory disturbance, bowel and bladder dysfunction, back pain and radicular pain (pain in the distribution of a single spinal nerve), sensation is diminished below the level of spinal cord involvement, tingling or numbness in the legs, pain, temperature sensation is diminished, appreciation of vibration (as caused by a tuning fork) and joint position sense may also be decreased, bladder and bowel sphincter control are disturbed in the majority of patients. Many patients with TM report a tight banding or girdle-like sensation around the trunk and that area may be very sensitive to touch. (Reference)

Myasthenia gravis

The symptoms of myasthenia gravis can include: severe and generalised muscle weakness (the first noticeable symptom frequently is weakness of the eye muscles). The disease may remain localised there, or progress to muscles involved in swallowing, chewing, talking, or in moving the limbs. Symptoms vary from patient, but can include a drooping of one or both the eyelids (ptosis), blurred or double vision, weakness of the muscles that move the eyeballs, and unstable or waddling gait, weakness in arms, hands, and fingers, difficulty in swallowing, and difficulty in breathing. Weakness tends to worsen with exercise and at the end of the day, and is usually particularly alleviated by rest. (Reference)

Mitochondrial myopathies

Depending on which cells of the body are affected, symptoms of mitochondrial myopathies can include: Poor growth, loss of muscle coordination, muscle weakness, visual and/or hearing problems, developmental delays, learning disabilities, mental retardation, heart, liver, or kidney disease, gastrointestinal disorders, severe constipation, respiratory disorders, diabetes, increased risk of infection, neurological problems including seizures, thyroid dysfunction, dementia (mental disorder characterized by confusion, disorientation, and memory loss) (Reference)

Symptoms of Behcet’s disease include: aphthous stomatitis (inflammation of the mucosa of the mouth) with the lesions healing in a few days to a month, but recurring (similar genital lesions recur less frequently). Ocular symptoms include posterior uveitis, iridocyclitis, a transient hypopyon (pus in the anterior chamber of the eye), iritis, and chorioretinitis (inflammation of the choroid and retina). Skin hypersensitivity. Vascular involvement includes thrombophlebitis (venous inflammation) of the large veins and arterial closing and aneurysm (dilation of an artery). Heart problems include: abnormal heart rhythms, missed heartbeats, early heartbeats and inflammation of the heart muscle. The lesions of aphthous stomatitis may be found elsewhere in the gastrointestinal tract. Symptoms vary from mild gastrointestinal discomfort to ulcerative colitis or regional enteritis and malabsorption problems. Arthritis occurs in about two-thirds of patients. Severe fatigue and malaise is common. The central nervous system is affected in about 23% of all patients with the disease (which may result in seizures, confusion, strokes, memory problems or headaches). (Reference) (Reference) (Reference)

Ulcerative colitis

Symptoms of ulcerative colitis include: diarrhea or rectal urgency, rectal bleeding, bloody diarrhea and mucus, rectal pain and an urgent need to empty your bowels, abdominal pain, constipation, loss of appetite, fever, weight loss and fatigue. Ongoing (chronic) symptoms, such as diarrhea, can lead to weight loss, anaemia and also: joint pain, eye problems, skin rash, or liver disease. (Reference) (Reference)

Kawasaki disease

The first symptom usually is a sudden, high fever that may be 104 F or higher that can last more than 10 days if the disease is not treated. Other symptoms often occur within a few days after the fever. These symptoms include: red, bloodshot eyes, usually without pus or discharge, a red body rash that varies in size, shape, and consistency, red, swollen, cracked lips and a red ("strawberry") tongue and lining of the mouth, firm, swollen hands and feet with shiny red palms and soles and swelling of lymph nodes on one side of the neck. Other symptoms may include: irritability and tiredness, joint swelling and pain, abdominal pain, vomiting, and diarrhea, a rapid heart rate or changes in heart rhythm from heart inflammation. (Reference)

Post-infectious polymyositis

Symptoms of Polymyositis can include: weak, tired and painful muscles mainly affecting the large muscles of the body, such as those around the shoulders, hips, and thighs (causing difficulty climbing stairs, getting up from low chairs, and getting in and out of the bath), muscles tender to the touch, feeling generally unwell (malaise), weight loss, night sweats. (Reference)

Vitamin B deficiency

Symptoms of vitamin B deficiency can include: mental problems, heart palpitations, heart arrythmias, indigestion, chronic fatigue, chronic exhaustion, paranoia, vague fears, fear that something dreadful is about to happen, nervousness, attention deficiency, inability to concentrate, irritability, feeling of uneasiness, thoughts of dying, easy agitation, frustration inability to sleep (insomnia), restlessness, tingling in hands fingers and toes, rashes, crying spells, inability to cope, soreness all over. (Reference)

Rheumatoid illness or lupus (SLE)

Symptoms of lupus can include: achy joints (arthralgia), frequent fevers of more than 100 degrees F., arthritis (swollen joints), prolonged or extreme fatigue, skin rashes, anemia, kidney involvement, pain in the chest on deep breathing (pleurisy), butterfly-shaped rash across the cheek and nose, sun or light sensitivity (photosensitivity), hair loss, abnormal blood clotting problems, raynaud's phenomenon (fingers turning white and/or blue in the cold), seizures, mouth or nose ulcers. (Reference) (Reference)

Sarcoma

Symptoms of Sarcoma include: joint swelling and tenderness, weight loss, fatigue, anemia, or pain without any clear source of injury, increasing abdominal pain, blood in stools or in vomit. (Reference)

Toxoplasmosis

Symptoms of Toxoplasmosis include: feeling off color, mild fever, enlarged neck lymph nodes, malaise, muscle pains, enlarged lymph nodes, enlarged glands, anemia, liver symptoms, low blood pressure, blood symptoms, eye symptoms, eye inflammation (Reference)

HIV/AIDS

Symptoms of early HIV infection can include: fever, headache, tiredness, nausea, diarrhoea and enlarged lymph nodes (organs of the immune system that can be felt in the neck, armpits and groin). Many people do not develop any symptoms when they first become infected with HIV. Some people, however, get a flu-like illness within three to six weeks after exposure to the virus. These symptoms usually disappear within a week to a month and are often mistaken for another viral infection. (Reference)

Lyme disease (Borrelia burgdorferi)

Symptoms of chronic Lyme disease can include: profound fatigue, unexplained fevers and chills, severe headache, severe muscle aches/pain, unexplained weight change (loss or gain), swollen glands, sore throat, unexplained sweats, night sweats, nerve conduction defects (weakness/paralysis of limbs, loss of reflexes, tingling sensations of the extremities - peripheral neuropathy), severe headaches, stiff neck, meningitis, cranial nerve involvement (e.g. change in smell/taste; difficulty chewing, swallowing, or speaking; hoarseness or vocal cord problems; facial paralysis - Bell's palsy; dizziness/fainting; drooping shoulders; inability to turn head; light or sound sensitivity; change in hearing; deviation of eyeball, stroke, abnormal brain waves or seizures, sleep disorders, cognitive changes (memory problems, difficulty in word finding, confusion, decreased concentration, problems with numbers), behavioral changes (depression, personality changes), panic attacks; disorientation; hallucinations; extreme agitation; impulsive violence, manic, or obsessive behavior (paranoia, schiziphrenic-like states), dementia, eating disorders, vision changes, including blindness, retinal damage, optic atrophy, red eye, conjunctivitis, "spots" before eyes, inflammation of various parts of the eye, pain, double vision, rash not at the bite site (this skin discoloration varies in size and shape; usually has rings of varying shades, but can be uniformly discolored; may be hot to the touch or itch; ranges in color from reddish to purple to bruised-looking; and can be necrotic (crusty/oozy). The rash may develop a bull's-eye rash or target look. The shape my be circular, oval, triangular, or a long-thin ragged line), irregular heartbeats, heart block, myocarditis, chest pain, vasculitis, intermittent or chronic joint pain (usually not symmetrical; sometimes swelling), TMJ-like pain in jaw, difficulty breathing, pneumonia. Shortness of breath, Cough, muscle pain and cramps, loss of muscle tone, nausea, vomiting, diarrhea, loss of appetite, anorexia. (Reference)

Tuberculosis

Early infection symptoms of tuberculosis include: fever, chills, sweating, night sweats, flu-like symptoms, gastrointestinal symptoms, weight loss, no appetite, weakness, fatigue. Symptoms of pulmonary tuberculosis include: persistent cough, chest pain, coughing up bloody sputum, shortness of breath, breathing difficulty, recurring bouts of fever, weight loss, progressive shortness of breath, cloudy urine or reddish urine. (Reference)

Brucellosis

Symptoms of Brucellosis include: Flu-like symptoms, fever, sweats, headaches, back pains, physical weakness, joint pain, enlarged liver, enlarged spleen, relapsing cycles of fevers. (Reference)

Anxiety neurosis

Symptoms of anxiety neurosis include: excessive anxiety and worry (apprehensive expectation), restlessness, easy fatigue, poor concentration, irritability, muscle tension (including trembling, twitching, feeling shaky, muscle aches, and soreness), disturbed sleep. (Reference)

Depression

Symptoms of depression include: abnormal depressed mood, loss of interest and decreased energy, loss of confidence, excessive guilt, recurrent thoughts of death, poor concentration, agitation or retardation, change in appetite, sadness, lethargy, helplessness, hopelessness, worthlessness, difficulties with decisions, changes to sleep patterns - difficulty sleeping or staying awake, changes in weight - either significant loss or gain in weight, relationship problems with partners, friends, family, colleagues, isolation, anxiousness, unusual fear or feeling panic. (Reference)

PTSD

The symptoms of PTSD include: severe fatigue, sleep problems including nightmares and waking early, flashbacks and replays which you are unable to switch off, impaired memory, forgetfulness, inability to recall names, facts and dates that are well known to you, impaired concentration, impaired learning ability (eg through poor memory and inability to concentrate), hypervigilance, exaggerated startle response, irritability, sudden intense anger, occasional violent outbursts, panic attacks, emotional hypersensitivity, joint and muscle pains which have no obvious cause, feelings of nervousness, anxiety, reactive depression, excessive levels of shame, embarrassment, survivor guilt, a feeling of having been given a second chance at life, undue fear, low self-esteem and shattered self-confidence, emotional numbness, anhedonia (inability to feel love or joy), feelings of detachment, avoidance of anything that reminds you of the experience, physical and mental paralysis at any reminder of the experience. (Reference)

Schizophrenia and other psychiatric disease

Symptoms of Schizophrenia include: delusions, hallucinations, disorganised thinking, disorganised behaviour, catatonic behaviour, withdrawal, loss of motivation and ambivalence (Avolition) (this may involve lack of energy, apathy or seeming absence of interest in what were usually routine activities. People experiencing avolition may be inattentive to grooming, personal hygiene, have difficulty making decisions and have difficulty persisting at work, school or household chores), loss of feeling or an inability to experience pleasure (Anhedonia), poverty of speech (Alogia), flat presentation (Affective Flattening), cognitive impairments (including problems with attention, concentration and memory). (Reference)

1. Diagnosis based on symptomatology only? Assessing a patient’s symptomatology is only one part of the process of diagnosis. Diagnosis cannot be and should not be made on the analysis of symptomatology alone (unless an illness, for example M.E., has symptoms or groups of symptoms which are unique to that one illness). Correct diagnosis must combine an analysis of the symptoms present with a thorough medical history, physical exam, and with appropriate testing. Unlike almost all of the illnesses listed here the onset of M.E. is always acute. So determining the type of onset – acute or gradual – is very important, for example. (See below for further information on the acute onset of M.E.) It is not appropriate to use these symptom lists alone to diagnose any illness. These lists are included merely to illustrate how easily many of these illnesses may be (and are) misdiagnosed as ‘CFS.’

2. M.E. is always an acute onset illness. Most people with M.E. will know not only the exact week and day they became ill, but even the exact hour that they suddenly became ill. The onset of M.E. is frequently very dramatic and patients can usually be diagnosed within 2 weeks of the onset of their illness.

Arbitrarily separating those with acute onset illness to the M.E. category, and those with gradual onset to being in the ‘CFS’ category is problematic however because (a) some sufferers will be unsure of their onset type (they may not recall it, or may not recall it accurately, for various reasons) and (b) in some cases, acute onset M.E. is preceded by a series of unrelated minor infectious episodes (in a previously well patient) which may be misinterpreted as being a gradual onset of the M.E. (These minor infectious episodes may be due to the immune system being under temporary or chronic stress from events such as; recent immunisation, repetitive contact with a large number of infectious persons, or the effect of travel; as in exposure to a new subset of virulent infections. This pre-existing temporary or chronic immune system weakness is not seen in all patients and is not what causes M.E., although a compromised immune system will of course make the bodies of those so affected somewhat more vulnerable to all types of infections, including M.E.)

M.E. must be diagnosed by looking at the patient's onset type, overall symptomatology, and pathology. If the symptomatology and pathology fit M.E. then it can only be M.E. regardless of the onset type noted (M.E. is a clearly defined disease process with several unique features/characteristics and known pathology), and either point (a) or point (b) will apply (Hyde 2006, [Online]) (Hyde 2007, [Online])

3. Similar illnesses? Despite claims to the contrary by some groups, M.E. is not the same illness (or even almost the same illness) as Lyme disease, Fibromyalgia, Gulf War Illness (GWI), MCSS, various post viral fatigue syndromes caused by glandular fever/mononucleosis etc. or any other illness. While these illnesses may have some symptoms in common with M.E., so do many other different illnesses. M.E. also has several unique features and symptoms which are not seen in any of these illnesses (for example the fact it occurs in epidemic and sporadic forms, the unique post exertional muscle weakness and worsening with exercise, the strong links with polio and post-polio syndrome, and so on). Although there are some similarities between the symptoms seen in these illnesses to some extent this does not mean that they represent the same etiological or pathobiological process, share the same core and essential symptoms, or will have the same or even a similar response to treatment, the same pathology, or a similar prognosis. They do not.

The idea of these very different patient groups being mixed up and treated as if they represented the exact same patient group is truly alarming. The results could only be disastrous for all concerned. Just like each of these illnesses Myalgic Encephalomyelitis is a distinct and unique illness and it is vitally important that they are each always seen that way for the benefit of all patients involved. Patients with all of these illnesses must be correctly diagnosed and treated based on studies involving only the same patient group! There is nothing to be gained by joining these illnesses as if they each referred to the same or only slightly different patient group as this is simply not the case. We must not let another 20 years be wasted mixing together vastly different patient groups unnecessarily!

4. I’m still confused… in a nutshell, what is the difference between M.E. and ‘CFS’? The terminology is often used interchangeably, incorrectly and confusingly. However, the DEFINITIONS of M.E. and CFS are very different and distinct, and it is the definitions of each of these terms which is of primary importance. The distinction must be made between terminology and definitions.

• Myalgic Encephalomyelitis is a systemic acquired illness initiated by a virus infection which is characterised by (scientifically measurable) damage to the brain stem which results in dysfunctions and damage to almost all vital bodily systems and a loss of normal internal homeostasis. M.E. also causes significant cardiac and cardiovascular abnormalities. The onset of M.E. is always acute. M.E. can be diagnosed within just a few weeks. M.E. is an easily recognisable distinct organic neurological disease which can always be verified by objective testing. If all tests are normal, then a diagnosis of M.E. cannot be correct. M.E. can occur in both epidemic and sporadic forms and can be extremely disabling, or sometimes fatal. M.E. is a chronic/lifelong disease that affects adults and children. Fatigue is not a defining symptom of M.E., nor even an essential symptom of M.E. M.E. is not a problem of ‘chronic fatigue.’ There are more than 64 M.E. symptoms. Symptoms range from mild to severe to life-threatening.
  
• Chronic Fatigue Syndrome is a man-made construct created in the US in 1988. It is not a distinct disease, but a mere diagnosis of exclusion based on the presence of the symptom of fatigue. CFS cannot be diagnosed until after 6 months have passed. If serious abnormalities are found on testing, a person no longer qualifies for a diagnosis of ‘CFS.’ (The fatigue in ‘CFS’ is ‘medically unexplained.’) The onset of ‘CFS’ may be gradual or acute. A diagnosis of ‘CFS’ does not mean that a person has any distinct disease, including M.E. In essence, every diagnosis of CFS can only ever be a misdiagnosis. ‘CFS’ is made up of people with a vast array of unrelated psychological and non-psychological illnesses with little in common but the symptom of fatigue.

M.E. is not synonymous with CFS, nor is it a subgroup of CFS. (There is no such thing as a subgroup of CFS; there is no such disease/s as "CFS.’) M.E. is not a primarily fatiguing condition, nor is it a wastebasket diagnosis or ‘medically unexplained’ as ‘CFS’ is. Sub-grouping different types of ’CFS,’ refining the bogus ‘CFS’ definitions further or renaming ‘CFS’ with some variation on the term M.E. would achieve nothing and only create yet more confusion and mistreatment. The problem is not that ‘CFS’ patients are being mistreated as psychiatric patients; some of those patients misdiagnosed with CFS actually do have psychological illnesses. There is no such distinct disease/s as ‘CFS’ – that is the entire issue, and the vast majority of patients misdiagnosed with CFS do not have M.E. and so have no more right to that term than to ‘cancer’ or ‘diabetes.’ The only way forward, for the benefit of society and every patient group involved, is that:

1. The bogus disease category of ‘CFS’ must be abandoned completely.
2. The name and definition of Myalgic Encephalomyelitis must be fully restored (to the exclusion of all others) and the World Health Organization classification of M.E. (as a distinct neurological disease) must be accepted and adhered to in all official documentations and government policy. Patients with M.E. must again be treated for and diagnosed with M.E. based on research involving genuine M.E. experts and actual M.E. patients.

There is no such disease/s as ‘CFS’ – the name CFS and the bogus disease category of CFS must be abandoned (along with the use of other vague and misleading umbrella terms such as ‘ME/CFS’ ‘CFS/ME’ 'ME-CFS' 'CFIDS' and 'Myalgic Encephalopathy' and others), for the benefit of all the patient groups involved, as well as the medical community and the general public.

• For more information see: The Terminology Explained, Why the disease category of ‘CFS’ must be abandoned, Myalgic Encephalomyelitis is not fatigue, or 'CFS' and What is M.E.?

5. I seem to fit the 2003 Canadian definition of ‘ME/CFS’ does this mean that I definitely have M.E.? No, it doesn’t. As the name suggests, this is a mixed M.E. and ‘CFS’ definition. It is essentially yet another redefinition of CFS, but with some of the symptoms (and other features) of M.E. tacked on. The Canadian ‘ME/CFS’ definition should not be considered a pure M.E. definition as it is possible to qualify for the diagnosis without having the unique and essential features of M.E.

• For more information see: Where to after a 'CFS' (mis)diagnosis? (Question and answer session)

6. Dual diagnosis? Despite the fact that severe pain is a well known and very common symptom of M.E. many M.E. sufferers who have pain are told that they now also supposedly have ‘Fibromyalgia.' But if pain is a recognised symptom of M.E. then how does an additional Fibromyalgia diagnosis made purely on the presence of pain make sense? Patients who have Fibromyalgia and patients with primary M.E. can be easily distinguished from each other with various tests (and other means including an evaluation purely based on symptomatology which is very different between the two illnesses), so what do tests show in patients who supposedly have both? Interestingly, when patients (supposedly) have both illnesses the test results given are the ones for M.E. only. So do these M.E. patients really also have Fibromyalgia, or do they just have severe pain as part of their M.E.? As you might expect, these test results strongly suggest the latter.

The same is true of multiple chemical sensitivity syndrome (MCSS); symptoms of chemical sensitivity are part of the core symptoms of M.E. and have long been associated with M.E.(as well as with several other autoimmune illnesses such as multiple sclerosis and Lupus) and so there is no need for an additional diagnosis of MCSS to be made. This additional diagnosis is incorrect. Just because you may fit a definition of Fibromyalgia, or MCSS, or irritable bowel syndrome (IBS) this does not mean that your symptoms are caused by the same etiological or pathological process, or will respond to various treatments the same way, or will have the same prognosis as those people who have primary Fibromyalgia, MCSS or IBS, and so on. All of these symptoms from pain to chemical sensitivities to constipation or diarrhoea are all very common symptoms of M.E. making additional diagnoses inappropriate.

• See M.E. and other illnesses and ME vs Fibromyalgia for more information.
• See: What is M.E.? for more information on all aspects of M.E. and ‘CFS

A Hummingbirds Guide to M.E. does not dispense medical advice or recommend treatment, and assumes no responsibility for treatments undertaken by visitors to the site. It is a research-information and advocacy resource only. Please consult your own health-care provider regarding any medical issues relating to the diagnosis or treatment of any medical condition.