The Facts

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a condition causing persistent fatigue that lasts for at least 6 months (or longer) and isn't due to another medical condition (e.g., hypothyroidism). It was once thought to affect only highly educated young adults who are "high achievers" or career-oriented professionals. It is now known that ME/CFS affects people of all ages and from all walks of life. While 25% of people report being chronically fatigued, only about 0.5% of the population meet the criteria for chronic fatigue syndrome.

ME/CFS is about 2 to 4 times more common in women than in men. Young and middle-aged people are most commonly affected, but ME/CFS may be present in all ages, including children. It is associated with extreme and prolonged fatigue that isn't relieved by rest. People with ME/CFS experience persistent tiredness so severe that it may prevent them from working, exercising, and enjoying life. ME/CFS is a poorly understood condition and there is no clear consensus about its diagnosis and treatment.

ME/CFS is also known as myalgic encephalomyelitis (ME), chronic fatigue immune dysfunction syndrome (CFIDS) or systemic exertion intolerance disease (SEID).


Until recently, many people suffering from ME/CFS symptoms were brushed off as psychiatric cases or were told "it's all in your head." However, ME/CFS is now recognized as a genuine medical condition.

We don't know exactly what causes ME/CFS, but it appears to be triggered by many different factors. Viral infections, genetic predisposition, environmental toxins, and immune reactions are all considered possible causes of the disorder. The persistent tiredness was once attributed to a virus called the Epstein-Barr virus (this virus is responsible for mononucleosis) but the link remains scientifically unproven and is no longer considered a potential cause

Several other potential causes of ME/CFS are being studied including issues with sleep disruption, endocrine-metabolic dysfunction (a disorder affecting your body’s metabolism and hormone balance), and neurally mediated hypotension (a certain kind of low blood pressure disorder). Two-thirds or more of people who have ME/CFS meet existing psychiatric criteria for anxiety disorders, depression, or dysthymia (mild, long-term depression), but whether these issues are the cause or the result of ME/CSF remains unclear. There is some evidence suggesting that ME/CFS is an immune disorder, meaning the body's defense system functions abnormally, particularly in response to stress. This does not mean that the immune system is weakened.

It's likely that not one single factor is responsible, but rather a combination of factors. Physical activity and physical or emotional stress seems to make ME/CFS worse. However, further research is needed to figure out its causes and to better understand this puzzling condition.

Symptoms and Complications

Extreme fatigue that lasts at least 6 months is the hallmark symptom of ME/CFS. The onset may be sudden. People who have ME/CFS are constantly exhausted and feel that their stamina is continuously low. Other symptoms include:

  • mild fever
  • sore throat
  • tender neck with swollen lymph nodes
  • decreased ability to concentrate
  • muscle weakness and joint pain
  • headaches
  • memory and concentration problems
  • difficulty sleeping

Problems with concentration and memory often occur. A person might have mental fogginess, impaired short-term memory, or the inability to concentrate to the point where regular activities are disrupted.

Other symptoms such as gastrointestinal problems, sleep disorders, or abnormal body temperatures are also commonly reported.

Symptoms may be severe enough to interfere with work performance, leading to sick leave and extended periods of bed rest. The symptoms of ME/CFS can last for several years. However, they're usually at their worst in the early stages of the illness. Some people never return to their original energy levels. Symptoms tend to reappear during times of emotional or physical stress.

Making the Diagnosis

Doctors diagnose ME/CFS based on symptoms. Symptoms should be present at least half of the time of the time and be moderate to severe in intensity.

In order to be diagnosed with ME/CFS people must have the following 3 symptoms:

  • reduced or impaired ability to perform normal daily activities, lasting for more than 6 months and accompanied by profound fatigue
  • worsening of symptoms with physical activity
  • unrefreshing sleep

Additionally, one of the following 2 symptoms must be met to confirm a diagnosis:

  • problems with thinking, memory, or information processing
  • feeling of dizziness or light-headedness when standing or maintaining an upright position, and improvement of symptoms when lying down

Treatment and Prevention

Although there are no recommended or proven treatments to date, management of ME/CFS includes reassurance and support about the condition and how things will improve with time. It is difficult to predict when and how much someone with ME/CFS will improve, since this varies a great deal between individuals.

Cognitive behavioural therapy and exercise (starting slow and increasing over time) appear to produce the most benefit. A doctor will likely combine a number of different treatments aimed at addressing your specific symptoms, including:

  • medical intervention and medications
  • alternative therapies
  • psychotherapy (cognitive behavioural therapy)
  • physical and lifestyle adjustments

Since no medication has been specifically proven to cure ME/CFS, medications are used to treat some of the symptoms that are seen with ME/CFS. For depression, antidepressants such as selective serotonin reuptake inhibitors (SSRIs; e.g., paroxetine*, sertraline) or tricyclic antidepressants (TCAs; e.g., amitriptyline, imipramine) may be used. Antianxiety medications such as lorazepam may be used to treat anxiety. Sleeping pills, such as zopiclone, may be used to treat certain sleep disorders, though referral to a sleep specialist may be necessary. Nonsteroidal anti-inflammatory drugs (NSAIDs) are used for headaches, fever, and general aches and pains. ME/CFS can sometimes go away on its own. Medications should therefore be tried for short periods and then stopped, and the person's status should be reassessed before continuing with medication treatment.

Some people seek alternative therapies, including massage, acupuncture, herbal products, and dietary supplements. Herbal preparations that have been used by some people with ME/CFS include astragalus, borage seed oil, bromelain, comfrey, echinacea, garlic, ginkgo biloba, ginseng, primrose oil, quercetin, St. John's wort, and shiitake mushroom extract.

The value of alternative remedies is questionable. With few exceptions, most of these remedies haven't been shown to be effective for treating ME/CFS patients. Many people believe that just because herbal products are "natural" they're also safe. This isn't always true: besides containing an active compound that may have medicinal properties, unrefined plant preparations also have other substances that can harm you.

Comfrey and high doses of ginseng, for example, are known to have harmful effects. As well, herbal preparations and dietary supplements can interfere with other medications you may be taking or cause side effects.

Before taking alternative remedies, talk to a doctor or pharmacist about what's safe and appropriate for your specific situation.

Psychotherapy is another strategy that can help people with ME/CFS and their families to cope with the symptoms of ME/CFS. Cognitive behavioural therapy may help alleviate some of the distress and concerns about ME/CFS and its effects on your work and personal life.

Physical and lifestyle changes may also be recommended. Prolonged lack of exercise can exacerbate physical weakness. A graded exercise regimen can be a means of restoring some of the loss of energy and stamina. "Graded" exercise means starting exercise slowly and gradually increasing the amount and intensity over time.

Learning ways to manage energy levels is important; for instance, overexertion during periods of good health can lead to a return of symptoms. Finding ways to cope and deal with physical and emotional stresses can help prevent a return of ME/CFS symptoms.

*All medications have both common (generic) and brand names. The brand name is what a specific manufacturer calls the product (e.g., Tylenol®). The common name is the medical name for the medication (e.g., acetaminophen). A medication may have many brand names, but only one common name. This article lists medications by their common names. For information on a given medication, check our Drug Information database. For more information on brand names, speak with your doctor or pharmacist.

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