Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)


Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a long-term illness that affects many body systems. People with this illness are not able to do their usual activities. Sometimes, they may be confined to bed. The condition can also be called systemic exertional intolerance disease (SEID).

One common symptom is severe fatigue. It does not get better with rest and is not directly caused by other medical problems. Other symptoms can include problems with thinking and concentrating, pain, and dizziness.

Alternative Names

CFS; Fatigue - chronic; Immune dysfunction syndrome; Myalgic encephalomyelitis (ME); Myalgic encephalopathy chronic fatigue syndrome (ME-CFS); Systemic exertion intolerance disease (SEID)


The exact cause of ME/CFS is unknown. It may have more than one cause. For example, two or more possible causes may work together to trigger the illness.

Researchers are looking into these possible causes:

Genetics or environmental factors may also play a role in the development of ME/CFS:


There are three main, or "core," symptoms in people with ME/CFS:

People with ME/CFS have persistent and profound fatigue and are unable to do activities they were able to do before the illness. This extreme fatigue is:

ME/CFS symptoms can become worse after physical or mental activity. This is called post-exertional malaise (PEM), also known as a crash, relapse, or collapse.

Sleep issues may include problems falling or staying asleep. A full-night's rest does not relieve fatigue and other symptoms.

People with ME/CFS also often experience at least one of the two following symptoms:

Other common symptoms include:

Exams and Tests

The Centers for Disease Control (CDC) describes ME/CFS as a distinct disorder with specific symptoms and physical signs. Diagnosis is based on ruling out other possible causes.

Your health care provider will try to rule out other possible causes of fatigue, including:

A diagnosis of ME/CFS must include:

There are no specific tests to confirm the diagnosis of ME/CFS. However, there have been reports of people with ME/CFS having abnormal results on the following tests:


There is currently no cure for ME/CFS. The goal of treatment is to relieve symptoms.

Treatment includes a combination of the following:

Some drugs can cause reactions or side effects that are worse than the original symptoms of the disease.

People with ME/CFS are encouraged to maintain an active social life. Mild physical exercise may also be helpful. Your health care team will help you figure out how much activity you can do, and how to slowly increase your activity. Tips include:

Relaxation and stress-reduction techniques can help manage chronic (long-term) pain and fatigue. They are not used as the primary treatment for ME/CFS. Relaxation techniques include:

It also may be helpful to work with a therapist to help you deal with your feelings and the impact of the illness on your life.

Newer medicine approaches are being researched.

Support Groups

Some people may benefit from taking part in an ME/CFS support group.

Outlook (Prognosis)

The long-term outlook for people with ME/CFS varies. It is hard to predict at the time that symptoms first start. Some people completely recover after 6 months to a year.

About 1 in 4 people with ME/CFS are so severely disabled that they can't get out of bed or leave their home. Symptoms can come and go in cycles, and even when people feel better, they may experience a relapse triggered by exertion or an unknown cause.

Some people never feel like they did before they developed ME/CFS. Studies suggest that you are more likely to get better if you receive extensive rehabilitation.

Possible Complications

Complications may include:

When to Contact a Medical Professional

Call your provider if you have severe fatigue, with or without other symptoms of this disorder. Other more serious disorders can cause similar symptoms and should be ruled out.

If you or someone you know is thinking about suicide, call or text 988 or chat You can also call 1-800-273-8255 (1-800-273-TALK). The 988 Suicide and Crisis Lifeline provides free and confidential support 24/7, anytime day or night.

You can also call 911 or the local emergency number or go to the hospital emergency room. DO NOT delay.

If someone you know has attempted suicide, call 911 or the local emergency number right away. DO NOT leave the person alone, even after you have called for help.


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National Institutes of Health. Studying long COVID might help others with post-viral fatigue ailments: similarities between long COVID and ME/CFS motivate research. August 8, 2022.

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Review Date: 4/30/2023
Reviewed By: Neil J. Gonter, MD, Assistant Professor of Medicine, Columbia University, New York, NY, and private practice specializing in Rheumatology at Rheumatology Associates of North Jersey, Teaneck, NJ. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
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