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What Is Chronic Fatigue Syndrome?

Chronic fatigue syndrome (CFS) is a complicated disease for doctors to diagnose — and even fully understand.

CFS is a chronic (long-lasting) condition that makes people feel very tired and weak. They can also have headaches, dizziness, or other physical symptoms. Sometimes they have emotional symptoms too, like anger or sadness.

Different people with CFS can have different symptoms. Many CFS symptoms are similar to those of other health conditions, like mono, Lyme disease, or depression. And the symptoms can vary over time, even in the same person.

This makes treating the illness complicated. No single medicine or treatment can address all the possible symptoms.

CFS is sometimes called myalgic encephalomyelitis (ME). “Myalgic” (pronounced: my-AL-jik) means muscle aches. “Encephalomyelitis” (pronounced: in-sef-uh-low-my-eh-LIE-tis) means that there may be inflammation in the brain or spinal cord.

What Are the Signs & Symptoms of Chronic Fatigue Syndrome?

Someone with chronic fatigue syndrome can have many possible symptoms. The most common ones include:

  • severe fatigue, which can make it hard to get out of bed and do normal daily activities
  • sleep problems, such as trouble falling or staying asleep, or not having a refreshing sleep
  • symptoms getting worse after physical or mental effort (called post-exertional malaise)
  • symptoms or dizziness that get worse after standing up or sitting upright from a lying down position
  • problems with concentration and memory
  • headaches and stomachaches

What Causes Chronic Fatigue Syndrome?

Scientists have been researching chronic fatigue syndrome for many years, but they still don't know for sure what causes it.

Many doctors believe that the way some conditions interact within the body and mind might leave some people at risk for CFS. For example, if someone has a and is under a lot of stress, the combination of these two things might make them more likely to develop CFS.

These things are believed to interact with each other in this way, putting some people at risk for CFS:

  • infections. Experts have wondered if infections like measles or Epstein-Barr virus (the virus that causes mono) might increase the risk for CFS. The role Epstein-Barr plays in CFS is not clear because studies have not confirmed it as a cause.
  • problems with the immune system or the nervous system
  • hormone imbalances
  • emotional stress
  • low blood pressure

Chronic fatigue syndrome can affect people of all ethnicities and ages, but it's most common in people in their forties or fifties. It's very rare in kids. A few teens do get CFS, and it affects more girls than guys.

Sometimes different people in the same family get CFS. This might be because the tendency to develop CFS is genetic, but more research is needed to see if this is true.

How Is Chronic Fatigue Syndrome Diagnosed?

Right now, there's no test to tell if someone has chronic fatigue syndrome. Doctors ask a lot of questions (about a person's and the health of family members, medicines, allergies, smoking and drinking habits, etc.). They also will do an exam.

Doctors also usually order blood, urine (pee), or other tests to check for conditions that cause similar symptoms. They may send a person to see other specialists, such as a sleep specialist or a neurologist, to help with the diagnosis.

A diagnosis of CFS is made after the symptoms have been present for at least 6 months. It often takes that long for tests results to come back and for consultants to see the person. But there's no need to wait 6 months to see a doctor and start treatment. Sometimes over the course of 6 months, the symptoms clear up, which might mean it was not CFS after all.

How Is Chronic Fatigue Syndrome Treated?

There's no known cure for chronic fatigue syndrome, but the symptoms can be treated. Experts suggest focusing on the most disruptive symptoms first, and working with a doctor to manage them:

  • Post-exertional malaise. For someone whose symptoms get worse after even mild activity, experts suggest “pacing” their activities. This means planning for a balance of activity and rest based on what the person feels are their limits. This can be different from one person to the next. Someone with CFS should not be pushed to do more than they feel they can tolerate, as this can lead to a “crash,” or worsening of symptoms.
  • Dizziness. People who get dizzy or feel weak or lightheaded when they sit up or stand might need to drink more fluids, use more salt in their foods, or wear support stockings.
  • Sleep problems. Getting good sleep can help someone overcome CFS-related sleep problems.
  • Problems with concentration and memory. Finding ways to keep track of important things (such as keeping lists and making notes) can help with concentration or memory problems.
  • Headaches and stomachaches. Gentle massage and heat may help some people with pain from CFS.

Doctors may also suggest over-the-counter (OTC) or prescription medicines for some of these symptoms.

Meeting often with a therapist or counselor can help in CFS treatment. So can getting involved in a support group for people with CFS. The main goal of therapy is to help people cope with the illness, which can be hard or stressful to live with. It will not help treat or cure the illness itself. Sometimes techniques like deep breathing, massage therapy, and yoga can reduce stress and make a person feel better.

What Else Should I Know?

  • Strong emotions can be a part of the illness, so it's important to recognize and express your feelings. Feelings like sadness, anger, and frustration are completely normal — and it's important to acknowledge how you feel and recognize that it's not your fault. Recognizing emotions (rather than suppressing them or pretending you're OK) can help you figure out what's behind your feelings and help you manage problems.
  • It can help to keep a daily diary of feelings and energy highs and lows. This also can let you share information that might help your doctor. You can also track trends — for example, if your energy is high at one time of day and low at another — that will help you figure out when to exercise or do other activities.
  • Give yourself more time to do things, especially activities that take concentration or physical exertion.
  • Get support from family, teachers, and friends.

Most important, don't give up. Having chronic fatigue syndrome can be hard. But for most people, the symptoms are most severe in the beginning. Later, they may come and go. Teens with CFS generally get better faster and recover more completely than adults do. Most teens get partial or full recovery within 5 years after symptoms began.

Try to keep a positive approach to getting well and to not look for the reason why you have CFS. People who take action and stay positive can have a good outcome.

You also can find more information and support online at:

Medically reviewed by: Elana Pearl Ben-Joseph, MD
Date reviewed: March 2022