What Is Chronic Fatigue Syndrome, and How Is It Treated?

Chronic fatigue syndrome — also called myalgic encephalomyelitis (ME/CFS) — affects up to 2.5 million people in the U.S. It is most commonly seen in women who are 40 to 60 years old. Despite its prevalence, it continues to be a poorly understood condition. We’ll review the most common symptoms, the current understanding of what causes ME/CFS, how it’s diagnosed, and how it’s treated. 

What causes chronic fatigue syndrome?

Experts are still trying to understand what causes ME/CFS. But until we have a more definitive answer, they have developed some theories:

• Past infections: Both viruses and bacterial infections have been linked to the development of ME/CFS. This includes past infection with Epstein Barr virus, Ross River virus, and Coxiella burnetti.

• Immune system dysfunction: ME/CFS has also been linked to an autoimmune process, or malfunctioning of the immune system.

• Abnormal response to stress: Cortisol — also known as the stress hormone — is normally released in the body when we are exposed to mental or physical stress. People with ME/CFS may have lower cortisol than normal, causing their immune system to flare. And some researchers think that this increased inflammation in the body leads to ME/CFS.

• Abnormalities in how energy is used by the body’s cells: Some studies have found that people with ME/CFS have problems with energy production in their cells. This can happen in muscle cells, which might cause some of the symptoms that people with ME/CFS experience — like muscle pain and fatigue.

• Genetics: Research is ongoing to find possible genetic links to ME/CFS. But the interaction of our genes with the environment likely influences the development of this disorder.

It’s likely a combination of these factors that lead to the development of ME/CFS. And there may be other factors that haven’t been discovered yet.   

What are the symptoms of chronic fatigue syndrome?

ME/CFS affects many different systems in the body. So people with this condition may experience a wide array of different symptoms. The hallmark symptom is debilitating fatigue that’s worse with activity and does not improve with rest. Everyday activities that most people take for granted — like running errands, taking a shower, or cooking a meal — often trigger such fatigue. 

People with this condition can have a multitude of other symptoms, such as: 

• Muscle weakness

• Muscle and joint aches

• Sleep problems

• Headaches

• Problems with concentration or memory, sometimes called “brain fog”

• Shortness of breath 

• Racing or irregular heartbeat, also called palpitations

• Problems with digestion, diarrhea, or constipation

• Swollen lymph nodes 

• Recurring sore throat

• Sensitivity to light, certain odors, foods, or noise

• Night sweats and chills

Everyone has a different combination of symptoms. And while there are many symptoms, most people don’t experience every one of them.

Diagnosis of chronic fatigue syndrome

There is no test for ME/CFS. The diagnosis is based on your symptoms and ruling out other possible explanations for them. Your healthcare provider can help with this process. 

After a history and physical exam, your provider may check blood or imaging tests to rule out other possible conditions. For example, your provider may check your blood counts and thyroid hormone levels to make sure your symptoms aren’t being caused by anemia or thyroid imbalance. And they may also perform an X-ray of your lungs or an electrocardiogram (ECG) of your heart if you are experiencing shortness of breath or palpitations. 

If no other cause is identified for your symptoms, your provider may suspect ME/CFS. In order to be diagnosed with ME/CFS, you must have three main symptoms:

1) Decreased ability to accomplish everyday tasks with debilitating fatigue that doesn’t improve with rest — and lasts for at least 6 months

2) Symptoms get worse after emotional or physical activity — known as post-exertional malaise  

3) Problems with sleep, such as the inability to fall or stay asleep, or waking up feeling unrefreshed 

At least one of the following two symptoms must also be present:

1) Problems with memory or focus

2) Worsening symptoms when standing or sitting upright, also called orthostatic intolerance

ME/CFS can be a difficult diagnosis to make. And some providers may not be as familiar with the symptoms or diagnostic criteria. This means that some people with ME/CFS are told that there’s nothing wrong because all the tests are negative. But keep in mind that you are the expert when it comes to your body. So if you think you may have ME/CFS, it’s helpful to find a provider who listens to your concerns and is willing to continue to look for the cause of your symptoms. 

Treatment of chronic fatigue syndrome

We are still learning a lot about ME/CFS. And until we understand what causes it, there’s no definitive treatment for it. But there are treatment strategies that can help to alleviate symptoms and make everyday activities possible. These strategies include:

• Pacing or activity management: This is a stepwise activity that is personalized to what you can tolerate without symptoms. It requires you to take note of the activities that trigger fatigue or other symptoms. And then you’ll need to learn how to not overdo that activity. With some effort, it’s possible to find the right individual balance of activity and rest.

• Cognitive behavioral therapy: This is a form of psychological therapy that can help you cope with symptoms. While it’s not a treatment for the symptoms themselves, many people find it useful as a strategy to help treat the anxiety and depression that can accompany ME/CFS.  

• Certain medications: Medications may be considered on a case-by-case basis, depending on the symptoms or accompanying conditions. These include pain relievers like NSAIDs or acetaminophen (Tylenol) for muscle aches, and antidepressants or antianxiety medications to help with mood problems or pain.

ME/CFS is a complex condition, and each person with this condition can have a different experience. Treatment strategies are personalized to fit the individual. 

What is my prognosis if I’m diagnosed with chronic fatigue syndrome?

This is a chronic condition, which means that it’s long term. It’s not curable, but many people learn to manage the symptoms over time. Finding the right treatments for you can take time, and this can change over the course of your lifetime. Communicate with your healthcare provider about your symptoms so you can work together to find the right treatment approach for you. 

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Written by:

Joanna Jan, MD

Joanna Jan, MD, is board-certified in internal medicine and licensed to practice medicine in the state of Pennsylvania. In 2017, she received her board certification from the American Board of Internal Medicine.

Edited by:

Katie E. Golden, MD

Katie E. Golden, MD, is a board-certified emergency medicine physician and a medical editor at GoodRx.

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