Patient Information

Chronic fatigue syndrome

Chronic fatigue syndrome
Stephen J Gluckman, MD
Section Editor
Peter F Weller, MD, FACP
Deputy Editor
Anna R Thorner, MD


Last literature review version 19.3: Fri Sep 30 00:00:00 GMT 2011 | This topic last updated: Thu Jan 20 00:00:00 GMT 2011 (More)

OVERVIEW — Chronic fatigue syndrome (CFS) is a disorder that causes unexplained, persistent, and sometimes debilitating fatigue.

Living with chronic fatigue syndrome can be frustrating because most people, including healthcare providers, have a limited understanding of why or how CFS develops. In addition, there are limited treatment options. Although CFS is not likely to shorten your life, it can have a profound effect on your quality of life.

More detailed information about chronic fatigue syndrome is available by subscription. (See “Clinical features and diagnosis of chronic fatigue syndrome” and “Treatment of chronic fatigue syndrome”.)

SYMPTOMS — Persistent fatigue is the hallmark of chronic fatigue syndrome.

  • Typically, the fatigue develops suddenly, often following an infection such as upper respiratory infection or mononucleosis. (See “Patient information: Infectious mononucleosis (mono) in adults and adolescents”.)
  • After the initial illness gets better, you are left with overwhelming fatigue and a number of additional symptoms.
  • Physical activity makes the symptoms worse.
  • Typically, people who develop CFS were functioning at a high level previously. You do not have a history of worrying excessively about being ill. You do not have multiple physical complaints, such as chronic back ache, chronic headache, and so on.

Many, if not most, people with CFS have physical symptoms for which no cause can be found with an examination and/or testing. In addition to the fatigue, you may have one or more of the following:

  • Sore throat
  • Memory and concentration problems
  • Generalized pain
  • Headaches
  • Difficulty sleeping
  • Tender lymph nodes (glands) in the neck and/or armpits

The bodywide nature of symptoms and lack of an identifiable cause can make coping with this disease difficult. People may suspect that you are making up the symptoms, and you may wonder if there is really anything wrong with you. Consequently, feelings of anger, frustration, and depression are common with CFS.

The signs and symptoms of CFS can also occur with other medical conditions. Thus, it is essential to see a healthcare provider and have other potential causes ruled out. However, CFS can also occur at the same time as other illnesses.

POSSIBLE CAUSES — The cause of CFS is not known. Past explanations for CFS have included chronic Epstein Barr virus infection, Lyme disease, total allergy syndrome, multiple chemical sensitivity syndrome, bodywide yeast infection, and viruses called xenotropic murine leukemia virus-related virus (XMRV) and murine leukemia virus. However, in carefully done research studies, none of these conditions has been proven to cause CFS. (See “Clinical features and diagnosis of chronic fatigue syndrome”.)

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Several other potential causes of CFS are being studied. There is some evidence suggesting that CFS is an immune disorder, causing the body’s defense system to function abnormally. This does not mean that the immune system is weakened, however.

Another line of research has focused on chronic hypotension (low blood pressure) caused by a problem in the nervous system.

RISK FACTORS — There are some groups of people who seem to be at higher risk for developing chronic fatigue syndrome.

  • CFS is diagnosed more often in young and middle-aged adults than in children or older adults.
  • CFS is diagnosed about twice as often in women as in men, and is also more likely to be diagnosed in white (non-Hispanic) people compared with other ethnic groups.

DIAGNOSIS — Chronic fatigue syndrome is usually diagnosed based upon a medical history and physical examination. Blood or urine testing may be done to rule out other conditions, but are not needed to diagnose CFS.

In order to be diagnosed with CFS, you must have unexplained, persistent, or relapsing fatigue, plus a number of the additional problems listed above. (See ‘Symptoms’ above.)

If you have unexplained chronic fatigue but few, if any, of these additional symptoms, you may have unexplained chronic fatigue. This is considered to be a different problem and is managed differently than CFS.

TREATMENT — There is no cure for chronic fatigue syndrome; the goal of treatment is to reduce symptoms of fatigue and help you to cope. Many therapies have been tried in CFS but none has been consistently successful. Cognitive behavioral therapy and graded exercise appear to be the most effective treatments. (See “Treatment of chronic fatigue syndrome”.)

Cognitive behavioral therapy — Cognitive behavioral therapy (CBT) is a type of therapy that can help to reduce symptoms of chronic fatigue syndrome. It typically involves a series of one-hour sessions with a psychotherapist or counselor. The sessions focus on discussing beliefs and behaviors that can interfere with your recovery. CBT will not cure CFS, but it can help you to cope better with your fatigue.

SEE MORE:  Chronic fatigue syndrome

Graded exercise — Although exercise can sometimes make chronic fatigue syndrome symptoms worse, a prolonged lack of exercise can also worsen CFS. Experts recommend beginning with gentle exercises and slowly increasing the intensity. Working with a professional trainer who is familiar with CFS may be of benefit.

Antibiotics — You or your clinician may be tempted to try a course of antibiotics, especially if you happen to have a positive blood test for Lyme disease. A positive Lyme test, however, merely indicates that you have been exposed to the bacteria that causes Lyme disease. It does not mean that your symptoms are related to Lyme disease. (See “Patient information: Lyme disease symptoms and diagnosis”.)

There is no role for antibiotics in the treatment of CFS, and there is the potential for serious side effects from prolonged use of antibiotics.

Treatment for fibromyalgia — Fibromyalgia is a condition that causes muscle and joint pain without an identifiable cause. Given the similarity between chronic fatigue syndrome and fibromyalgia, some clinicians treat both illnesses, beginning with education and one or more medications. (See “Patient information: Fibromyalgia”.)

Unproven treatments — Treatments that are not proven to improve symptoms of chronic fatigue syndrome include the following:

  • Medications — This includes antidepressant medications, antibiotics, and antiviral drugs, including doxycycline, amantadine, and acyclovir, medications that affect the immune system, glucocorticoids (also called steroids), and cimetidine or ranitidine (antihistamines used to treat heartburn)
  • Vitamin, mineral, or herbal supplements — These include magnesium, evening primrose oil, vitamin B12, and bovine (cow) or porcine (pig) liver extract
  • Exclusion diets, in which certain foods are eliminated or minimized
  • Removal of dental fillings
  • Medications used to treat human immunodeficiency virus

LIVING WITH CHRONIC FATIGUE SYNDROME — Although no specific treatment for CFS has been established, it is important to understand that CFS is not a new disease, and that there is considerable knowledge and experience with CFS. Some points to remember include:

  • The severity of CFS is variable, but the symptoms are real and the condition can be completely incapacitating. The symptoms are not made up. Because there are no laboratory or other tests to prove the existence of CFS, many people struggle with the validity of their disease (as do their healthcare providers, family members, friends, and employers).
  • There is no point to debating whether symptoms of CFS originate in your mind or are the result of a not-yet identified abnormality. If the cause is in your mind, the symptoms are no less real (a difficult concept for some patients and/or their families). If the cause is an abnormality in your body, it is not yet known how to find it or treat it.
  • Most people with CFS have some degree of depression. Depression can be successfully treated, and treatment can help people with CFS to cope better. (See “Patient information: Depression treatment options for adults”.)
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Research into the long-term course of CFS has yielded somewhat conflicting results. Some patients have an improvement in their symptoms over time while others worsen. Regardless of the long term prognosis, CFS does not result in organ failure or death.

The most important factor in your ability to successfully cope with CFS is establishing a strong relationship with an experienced healthcare provider. This should include trust on both sides and a willingness to believe that CFS is both real and disabling.

WHERE TO GET MORE INFORMATION — Your healthcare provider is the best source of information for questions and concerns related to your medical problem.

Related topics for patients, as well as selected articles written for healthcare professionals, are also available. Some of the most relevant are listed below.

Patient Level Information:

Patient information: Infectious mononucleosis (mono) in adults and adolescents
Patient information: Lyme disease symptoms and diagnosis
Patient information: Fibromyalgia
Patient information: Depression treatment options for adults

Professional Level Information:

Approach to the adult patient with fatigue
Clinical features and diagnosis of chronic fatigue syndrome
Postural tachycardia syndrome
Treatment of chronic fatigue syndrome

The following organizations also provide reliable health information.

  • National Library of Medicine


  • Centers for Disease Control and Prevention

404-639-1388 or 1-888-232-3228

  • National CFS and Fibromyalgia Association

Telephone: 816-737-1343

  • Chronic Fatigue and Immune Dysfunction Syndrome Association of America



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  2. Straus SE. Pharmacotherapy of chronic fatigue syndrome: another gallant attempt. JAMA 2004; 292:1234.
  3. Prins JB, van der Meer JW, Bleijenberg G. Chronic fatigue syndrome. Lancet 2006; 367:346.
  4. Wessely S. Chronic fatigue: symptom and syndrome. Ann Intern Med 2001; 134:838.