Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)


What is myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)?

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is persistent and crippling fatigue (exhaustion) lasting 6 months or longer. People living with ME/CFS often experience other symptoms, like unrefreshing sleep and muscle aches. The condition is also sometimes called chronic fatigue syndrome.

Doctors do not know what causes ME/CFS, and there is no cure. You may be able to manage symptoms with cognitive-behavioral therapy, exercise, and medications, like antidepressants and sleep aids. The goal of treatment is to make symptoms as manageable as possible to increase your quality of life.

Who is most at risk for getting myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)?

Women are more likely than men to develop ME/CFS. Young children and teenagers can develop ME/CFS, but the syndrome is much more common in adults.

How common is myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)?

The number of people with ME/CFS is not clear; some estimates put the number at 1 million people in the US, while another estimate is as high as 2.5 million people. Many of these individuals have not received a diagnosis, even though they live with this condition.

Symptoms and Causes

What are the symptoms of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)?

For many people, the symptoms of ME/CFS resemble other diseases, like influenza. Symptoms may come and go over time and may increase or decrease in severity. ME/CFS symptoms vary widely from person to person.

Many of the symptoms of ME/CFS make daily life difficult. These symptoms include:

  • Severe fatigue lasting at least 6 months that does not improve with rest or sleep
  • Difficulty sleeping
  • Flu-like symptoms, including swollen lymph nodes (small immune system structures that filter harmful substances), headaches, and joint pain
  • Cognitive (thinking) difficulties, including attention and memory problems
  • Muscle aches

Less common symptoms of ME/CFS include:

  • Problems with vision
  • Chills
  • Night sweats
  • Irritable bowel, an intestinal condition causing painful bloating, gas, constipation and diarrhea
  • Psychological (mental health) issues, including mood swings, irritability and anxiety
  • Tingling or numbness in the feet, hands or face

For many people, ME/CFS symptoms get worse following physical exercise or strenuous mental exertion. In some cases, orthostatic intolerance (symptoms that get worse if you stand or sit upright) causes dizziness, weakness, and fainting.

What causes myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)?

Doctors do not know what causes ME/CFS.

Diagnosis and Tests

How is myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) diagnosed?

Your doctor diagnoses ME/CFS by performing a mental and physical examination. Doctors will ask about your medical history and order blood and urine tests to check for infection. In many cases, doctors refer people with suspected ME/CFS to other specialists to rule out other illnesses that could be causing symptoms.

For your doctor to diagnose ME/CFS, you must have these 3 symptoms:

  • Severe fatigue lasting at least 6 months that does not improve with rest or sleep
  • Difficulty sleeping
  • Fatigue that gets worse after mental or physical exercise

Additionally, you must have at least 1 of the following symptoms:

  • Orthostatic intolerance
  • Cognitive difficulties

Management and Treatment

How is myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) treated?

There is no cure for ME/CFS. Treatment goals include managing symptoms and returning you to a higher quality of life. Some people aren’t able to regain the level of health and function they had before their diagnosis.

First, your doctor works with you to determine which symptoms cause the most difficulty. Together, you will address those symptoms immediately.

Counseling is helpful for many people with ME/CFS. This type of treatment helps people better tolerate symptoms by changing thoughts and behaviors. Your doctor may prescribe medications, like antidepressants or sleep aids, if your symptoms are especially severe. These medications can relieve symptoms like unrestful sleep for some people living with ME/CFS.

Before prescribing sleep aids, however, your doctor may provide suggestions for improving sleep without drugs. For instance, he or she might suggest that you visit a sleep specialist. Other tips include:

  • Develop a regular bedtime routine—go to bed and wake up at the same time each day.
  • Do not nap for more than 30 minutes total during the day.
  • Use your bed and bedroom only for sleeping and sex. Take out all electronics.
  • Avoid eating large meals before you go to bed; also avoid alcohol and caffeine.
  • Do your exercising at least 4 hours before you go to sleep.

Patients have to be careful to not over-extend their activity in a day. They need to pace themselves in the quantity of both mental and physical exertion in a day so that it does not take more than 24 hours to recover. Taking rest breaks and alternating the physical and mental tasks can be helpful.

Your doctor may recommend that you join a support group for people living with ME/CFS. These groups can help you cope with the condition by putting you in touch with others who know exactly what you’re going through.


Can myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) be prevented?

Currently, there is no known way to prevent ME/CFS.

Outlook / Prognosis

What are the outcomes after treatment for myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)?

With treatment, most ME/CFS symptoms improve. However, some people do not return to the same health or functional state as before their symptoms appeared.

Living With

What complications are associated with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)?

For some people, the fatigue associated with ME/CFS makes activities of daily living very difficult or even impossible. Research shows that only half of all people diagnosed with ME/CFS work full-time or part-time jobs.

ME/CFS causes significant depression in many people living with the condition. If you experience depression, talk with your doctor — effective treatments are available.

When should I call my doctor?

If you develop symptoms of ME/CFS, especially if they last 6 months or longer, contact your doctor. Your doctor will evaluate you and develop a treatment plan based on your unique symptoms.

Last reviewed by a Cleveland Clinic medical professional on 06/21/2018.


  • Merck Manual Professional Version. Chronic Fatigue Syndrome. ( Accessed 6/27/2018.
  • U.S. Department of Health and Human Services. Chronic fatigue syndrome. ( Accessed 6/26/2020.
  • Centers for Disease Control and Prevention. What is ME/CFS? ( Accessed 6/27/2018.

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