Chronic Fatigue Syndrome vs Fibromyalgia: What’s the Difference?

By Nicole Villeneuve

Published March 1, 2023

Chronic fatigue syndrome vs fibromyalgia

Chronic fatigue syndrome and fibromyalgia have several symptoms in common. Both conditions can cause pain in the muscles or joints, fatigue, problems with thinking and memory, and unrefreshing sleep. So, are chronic fatigue syndrome and fibromyalgia the same thing? What are the differences between chronic fatigue syndrome vs fibromyalgia?

In this article, we’ll take a closer look at the two conditions, including the symptoms that distinguish them. We’ll talk about the difference between a chronic condition and a progressive one, and we’ll discuss the treatments doctors often recommend for fibromyalgia and chronic fatigue syndrome. With this information, you’ll be in a better position to get an accurate diagnosis.

What Is the Definition of a Chronic Condition?

For many people, the most important question is not exactly what condition they have but instead is how it can affect their lives: how bad it might get, whether they can expect to feel better, and how soon their symptoms might improve. So let’s start by answering some questions about what it means to have a chronic condition.

Is Fibromyalgia a Chronic Illness?

When we say that a condition is chronic, we mean that the symptoms come on slowly and last several months or longer, depending on the diagnostic criteria for the specific condition. Diabetes, arthritis, and many kinds of cancer are chronic. An acute condition, on the other hand, comes on quickly, and it typically gets better within six months. Heart attack, broken bones, and flu are acute. 

As its name suggests, chronic fatigue syndrome is a chronic illness. To meet the criteria for diagnosis, the symptoms must have lasted at least six months. 

But is fibromyalgia an acute or chronic condition? In the beginning, fibromyalgia symptoms can show up in a way that makes the condition seem to be acute. They often begin after an injury, infection, surgery, or very stressful life event. But this isn’t always the case. For some people, the symptoms emerge gradually, without a clear trigger. And they typically last a long time. By definition, the main symptom of widespread pain must have been present for at least three months.

A small fraction of people with fibromyalgia report that their symptoms eventually clear up entirely.¹ However, for most people, fibromyalgia does not go away completely. It is generally understood to be a chronic condition. There is no known cure for fibromyalgia, but with effective treatment, the symptoms can be managed so that people with fibromyalgia can live the life they want.

Can Fibromyalgia Get Worse?

It can be discouraging to have a medical problem that causes uncomfortable symptoms or gets in the way of living your life the way you’d like to. Many people who learn that they have a chronic condition feel distressed by the idea that it will never go away. They may also worry that it will get significantly worse as time goes on.

There is an important difference between a condition that is chronic and one that is progressive. “Chronic” simply means that the condition is likely to last a long time. It doesn’t necessarily mean that it’s very uncomfortable or even that you will have symptoms. People with some chronic conditions, such as hypertension (high blood pressure), experience no symptoms at all. With a chronic condition that does cause symptoms, like fibromyalgia, there may be ups and downs – times when you feel worse along with times when your symptoms are mild or go away completely.

The fact that a condition is chronic also doesn’t mean that the condition will necessarily get worse over time. In fact, the symptoms of chronic conditions can potentially improve quite a bit – either on their own or because you are getting effective treatment.

A progressive condition, on the other hand, will get worse as time goes on. Unlike a chronic condition, which fluctuates, a progressive condition generally won’t allow you those periods of feeling close to normal. With some progressive conditions, your health is likely to deteriorate quickly. With others, the change is very slow, meaning that it may be a long time before your health and functioning are significantly affected. But whatever the speed of change, a progressive condition will most likely be worse at some point in the future than it is now.

So, is fibromyalgia progressive? Researchers are still learning how this condition plays out over time. Generally speaking, fibro is not considered progressive. Some people do find that their symptoms get worse over time, but others have long stretches of time with no symptoms at all.

How about chronic fatigue syndrome? The short answer is that we don’t know for sure, but it seems that CFS is not necessarily progressive either. Although the symptoms may go on for a long time, they are typically worst in the first year or two, and many people find that their symptoms gradually improve over time. A small percentage of people recover completely.

If you are living with either fibro or CFS, focus on figuring out which treatments work best for you, and don’t give up hope. There is always the possibility of improvement.

Chronic Fatigue Syndrome

With all that said, let’s take a closer look at the symptoms of these two conditions, beginning with chronic fatigue syndrome. This condition is increasingly being referred to as myalgic encephalomyelitis, or ME/CFS. The new name is believed to be a more complete description of the symptoms. It also reflects the fact that ME/CFS is now considered a disease rather than a syndrome.

Primary Symptoms of Chronic Fatigue Syndrome

The three main symptoms of CFS are:

  • extreme fatigue
  • difficulty recovering after physical or mental activity
  • feeling unrefreshed even after a full night’s sleep

To be diagnosed with CFS, you must have all three of those symptoms, plus either problems with thinking, memory, and concentration (“brain fog”); or dizziness that worsens when you sit up or stand up; or both. These symptoms must last for six months or more, and they must be present to a moderate or severe degree at least half of the time.

Many people with CFS also have pain, but pain is not required to qualify for the diagnosis. If there is pain, it may take the form of joint pain, muscle aches, or headaches. Some people also have frequent sore throat, tenderness in the lymph nodes, intolerance of certain foods or drugs, or heightened sensitivity to sounds, smells, or light.

Note that fatigue is the hallmark symptom of CFS. The fatigue of CFS is much more than just feeling tired: it happens even if you haven’t engaged in activities that are typically tiring, and resting does not help. Essentially, it becomes difficult or impossible to do things that would have been normal for you before. If you have CFS, even an ordinary activity like taking a shower can cause fatigue that wipes you out for several days or even longer. People with CFS typically find it difficult to work or do other things they need to do. If you do not experience this degree of fatigue, your symptoms may be better explained by another diagnosis.

Treatments for Chronic Fatigue Syndrome

Since there is no cure for chronic fatigue syndrome, the main treatment approach is to manage symptoms, starting with the ones that bother you the most. Pacing can be very helpful in managing the fatigue and the “crashes” after activity. Pacing means keeping careful track of your daily activities and the symptoms that follow, to discover how much is too much. Once you know your limits, you can do just that much and no more, to reduce the risk that you’ll crash.

Medications can also be helpful for some people. If pain is an issue for you, over-the-counter or prescription pain medications may help. Some people with CFS also develop depression, and antidepressants may help with mood, as well as with pain and sleep. Certain medications may also help with dizziness that comes on when you stand up.

If you’re not sleeping well, tiredness can make your other CFS symptoms worse. Strategies to improve your sleep can also boost your overall well-being.


What are the symptoms of fibromyalgia? And how do they differ from chronic fatigue syndrome? Let’s take a look.

Primary Symptoms of Fibromyalgia

Unlike with CFS, the main symptom of fibromyalgia is “significant and widespread pain.” This occurs alongside other severe symptoms – namely fatigue, problems with thinking and memory, and waking unrefreshed. The pain and other symptoms must have been present most of the time for at least three months.

Fibromyalgia causes pain in the joints, muscles, tendons, and ligaments. It is usually a lingering, dull, achy feeling rather than a sharp or intermittent pain. It can also take the form of muscle spasms. The pain shows up on both sides of the body, and in both the upper and lower body.

Like CFS, fibromyalgia can cause fatigue that makes it very challenging to do things that other people find easy, or that you would have found easy before you became ill. With either condition, you can get exhausted doing something you want or need to do, then be sidelined for a few days or more. Fibromyalgia can also cause difficulty focusing, concentrating, or paying attention. It can be hard to remember things that happened recently. Some people describe these cognitive symptoms as “fibro fog.” And finally, people with fibro often wake up feeling tired, even if they’ve gotten a full night’s sleep.

Chronic, widespread pain is the hallmark of fibromyalgia. If you do not experience significant pain throughout your body, fibromyalgia may not be the best explanation for your symptoms.

Treatments for Fibromyalgia

Medications are commonly used to help with fibromyalgia symptoms. For pain, your doctor may recommend over-the-counter or prescription medications. Certain antidepressants also may help with pain or associated symptoms like fatigue. But medication is not the only treatment for fibro. There are a number of other things that can help, and some of them may even work better than medication.

Cognitive behavioral therapy (CBT) can be very effective for fibromyalgia.² CBT and related therapies such as acceptance and commitment therapy (ACT) help you work with your thoughts and behaviors, including those related to your symptoms. When you learn to see your symptoms differently, you may suffer less and feel freer to do the things that matter most to you. Relaxation and stress reduction techniques can also be helpful in managing fibromyalgia symptoms or pain flares.³

If you work up to it gradually, gentle physical exercise can be very beneficial in reducing fibromyalgia pain.⁴ Pacing your activities carefully can help reduce the chance that you’ll overdo it in a way that makes your symptoms flare up. This is true of both regular daily activities, like household chores, and exercise.

Receiving a Diagnosis: Chronic Fatigue Syndrome vs Fibromyalgia

If you think chronic fatigue syndrome and fibromyalgia sound confusingly similar, you’re right. There is a big overlap in their symptoms. This means it can be difficult even for a qualified physician to tell the difference. Both may involve changes in how the central nervous system processes and interprets sensory input. And it’s possible to have both fibromyalgia and chronic fatigue syndrome

Fortunately, the two conditions are treated in very similar ways, so it may not be necessary to distinguish between them perfectly in order to get started on the road to relieving your symptoms.

There is no single lab test or scan that can conclusively diagnose either CFS or fibromyalgia. Instead, your doctor will typically perform a physical exam and interview you extensively about what you’re experiencing. You can also perform a self-assessment to see if you meet the diagnostic criteria. You may need to see a specialist to get the right diagnosis.

Learning that you have either fibromyalgia or chronic fatigue syndrome (or both) can bring up a range of feelings. Fibro and CFS can have big effects in just about every area of your life. Receiving such a diagnosis can be discouraging. On the other hand, if you have been trying for a long time to find an explanation for your symptoms, it can be a relief to finally put a name to your experience. A thoughtful and well-informed clinician can reassure you that what you’re going through is not “all in your head”; you are living with a real medical condition.

However you’re feeling now, there is hope that you can feel better. Keep the lines of communication open with your doctor, and don’t be afraid to advocate for yourself. You may need to look into a specialist in fibromyalgia. With good treatment and a flexible attitude, you can expect to get some relief from your symptoms and live your life more the way you want to.

Medically Reviewed by Dr. Andrea Chadwick, MD


¹ Isomeri, R., Mikkelsson, M., Partinen, M., & Kauppi, M. J. (2018). Severity of symptoms persists for decades in fibromyalgia: A 26-year follow-up study. Clin Rheumatol. 37(5):1383–88. doi:10.1007/s10067-017-3967-0

² Thieme, K., Flor, H., & Turk, D.C. (2006). Psychological pain treatment in fibromyalgia syndrome: Efficacy of operant behavioural and cognitive behavioural treatments. Arthritis Res Ther 8, R121. https://doi.org/10.1186/ar2010

³ Kaplan, K. H., Goldenberg, D. L., & Galvin-Nadeau, M. (1993). The impact of a meditation-based stress reduction program on fibromyalgia. General hospital psychiatry 15(5), 284–89. https://doi.org/10.1016/0163-8343(93)90020-o

⁴ Busch, A. J., Webber, S. C., Brachaniec, M., Bidonde, J., Bello-Haas, V. D., Danyliw, A. D., Overend, T. J., Richards, R. S., Sawant, A., & Schachter, C. L. (2011). Exercise therapy for fibromyalgia. Curr Pain Headache Rep. 15(5):358-67. doi: 10.1007/s11916-011-0214-2

Nicole Villeneuve

Swing Marketing Director

Nicole Villeneuve is a Marketing Director at Swing Therapeutics, which develops digital therapies that help people with chronic illness live their best lives. She has written about behavioral health and chronic conditions for over a decade, and is a CDC-certified lifestyle coach for the National Diabetes Prevention Program.

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