Chronic fatigue syndrome

Chronic fatigue syndrome


Chronic fatigue syndrome (CFS) causes persistent fatigue (exhaustion) that affects everyday life and doesn’t go away with sleep or rest. 

CFS is also known as ME, which stands for myalgic encephalomyelitis. There’s some debate over the correct term to use for the condition, but these pages will refer to the condition as CFS.

CFS is a serious condition that can cause long-term illness and disability, but many people – particularly children and young people – improve over time.

Who is affected?

It’s estimated around 250,000 people in the UK have CFS.

Anyone can get the condition, although it’s more common in women than men.

It usually develops when people are in their early 20s to mid-40s. Children can also be affected, usually between the ages of 13 and 15. 

How it affects quality of life

Most cases of CFS are mild or moderate, but up to one in four people with CFS have severe symptoms. These are defined as follows: 

  • mild – you’re able to care for yourself, but may need days off work to rest
  • moderate – you may have reduced mobility, and your symptoms can vary; you may also have disturbed sleep patterns and need to sleep in the afternoon
  • severe – you’re able to carry out minimal daily tasks, such as brushing your teeth, but have significantly reduced mobility, and may also have difficulty concentrating

Read more about the symptoms of CFS.

Why it happens

It’s not known exactly what causes CFS. Various theories have been suggested, including:

  • a viral or bacterial infection
  • problems with the immune system
  • an imbalance of hormones
  • psychiatric problems, such as stress and emotional trauma

Some people are thought to be more susceptible to the condition because of their genes, as the condition is more common in some families.

More research is needed to confirm exactly what causes the condition.

Read more about the causes of CFS.

How it is diagnosed

There are specific guidelines issued by the National Institute for Health and Care Excellence (NICE) about the diagnosis and management of CFS.

NICE says a diagnosis of CFS should be considered if you meet specific criteria regarding your fatigue – for example, it can’t be explained by other conditions – and if you also have other symptoms, such as sleeping problems or problems thinking and concentrating.

The diagnosis can then be confirmed if these symptoms are experienced for several months.

Read more about diagnosing CFS.

How it is treated

Treatment for CFS may be able to reduce the symptoms. Everyone with CFS responds to treatment differently, so your treatment plan will be tailored to you.

Some of the main treatments include:

Most people with CFS improve over time, although some people don’t make a full recovery. It’s also likely there will be periods when symptoms get better or worse. Children and young people with CFS are more likely to recover fully.

Read more about treating CFS.

Symptoms of chronic fatigue syndrome

The symptoms of chronic fatigue syndrome (CFS) vary from person to person, and generally there may be good periods and bad periods.

There may be times when your symptoms improve and you’ll be able to do many normal everyday activities. At other times, symptoms may flare up and get worse, affecting your daily life.


The main symptom of CFS is persistent physical and mental fatigue (exhaustion). This doesn’t go away with sleep or rest and limits your usual activities.

Most people with CFS describe this fatigue as overwhelming and a different type of tiredness from what they’ve experienced before.

Exercising can make symptoms worse. This is called post-exertional malaise, or “payback”. The effect of this is sometimes delayed – for example, if you were to play a game of sport, the resulting fatigue may not develop until a few hours afterwards, or even the next day.

People with severe CFS are unable to do any activities themselves or can only carry out simple daily tasks, such as brushing their teeth. They’re sometimes confined to their bed and are often unable to leave their house. 

Other symptoms

There are other common symptoms as well as fatigue, although most people don’t have all of them. They include:

  • muscular pain, joint pain and severe headaches
  • poor short-term memory and concentration, and difficulty organising thoughts and finding the right words (“brain fog”)
  • painful lymph nodes (small glands of the immune system)
  • stomach pain and other problems similar to irritable bowel syndrome, such as bloating, constipationdiarrhoea and nausea
  • sore throat 
  • sleeping problems, such as insomnia and feeling that sleep isn’t refreshing
  • sensitivity or intolerance to light, loud noise, alcohol and certain foods
  • psychological difficulties, such as depression, irritability and panic attacks
  • less common symptoms, such as dizziness, excess sweating, balance problems and difficulty controlling body temperature

Causes of chronic fatigue syndrome

Exactly what causes chronic fatigue syndrome (CFS) is unknown, but there are several theories.

Some experts think a viral infection such as glandular fever can trigger the condition. Certain bacteria have also been suggested as a cause of CFS in some people, including types of bacteria responsible for pneumonia.

However, while tiredness is normal after a viral infection, this doesn’t explain why symptoms persist and get worse in CFS. Also, many cases of CFS don’t start after an infection, and this theory doesn’t explain why the condition sometimes develops gradually.

Other suggested causes of CFS include:

  • problems with the immune system
  • a hormone imbalance
  • psychiatric problems – some cases have been linked to mental exhaustion, stress, depression and emotional trauma
  • genes – some people may have an inherited tendency to develop CFS as it’s more common in some families
  • traumatic events – some cases have been linked to events such as surgery or a serious accident

It’s possible CFS is caused by a combination of factors. Further research is necessary to confirm what causes the condition.

Debate over classification

The World Health Organization (WHO) has classified CFS as a chronic (long-term) neurological condition and this classification has been accepted by the Department of Health. However, the WHO’s decision remains controversial and isn’t accepted by everyone working in the field.

Members of the team of health professionals who drew up the National Institute of Health and Care Excellence (NICE) guidelines for CFS couldn’t agree that this classification is the right decision, and 84% of members of the Association of British Neurologists surveyed in 2011 said they didn’t view CFS as a neurological condition.

Diagnosing chronic fatigue syndrome

There’s no test for chronic fatigue syndrome (CFS), but there are clear guidelines to help doctors diagnose the condition.

It can take a long time for CFS to be diagnosed, as other conditions that cause similar symptoms need to be ruled out first.

You may be given some advice about managing your symptoms before a diagnosis is confirmed. See treating CFS for more information.

If you see your GP about persistent and excessive fatigue, they’ll ask you about your medical history and may carry out a physical examination.

You may have blood tests, urine tests and scans to rule out other conditions, such as anaemia (lack of red blood cells), an underactive thyroid gland, or liver and kidney problems.

NICE guidelines for diagnosing CFS

Guidelines released in 2007 from the National Institute for Health and Care Excellence (NICE) state doctors should consider diagnosing CFS if a person has fatigue and all of the following apply:

  • it is new or had a clear starting point (it has not been a lifelong problem)
  • it is persistent or recurrent, or both 
  • it is unexplained by other conditions
  • it substantially reduces the amount of activity someone can do
  • it feels worse after physical activity

The person should also have one or more of these symptoms:

  • difficulty sleeping or insomnia
  • muscle or joint pain without inflammation 
  • headaches 
  • painful lymph nodes that are not enlarged
  • sore throat 
  • poor mental function, such as difficulty thinking
  • symptoms getting worse after physical or mental exertion
  • feeling unwell or having flu-like symptoms
  • dizziness or nausea
  • heart palpitations without heart disease

This diagnosis should be confirmed by a clinician after other conditions have been ruled out. The symptoms listed above must have persisted for at least four months in an adult and three months in a child or young person.

For more information, read the NICE guidelines on CFS.

Chronic fatigue syndrome or PoTS?

It’s likely some people diagnosed with chronic fatigue syndrome actually have postural tachycardia syndrome (PoTS).

PoTS is an abnormal increase in heart rate after sitting or standing up, which typically causes dizziness, fainting, sweating and other symptoms.

Read more about PoTS.

Treating chronic fatigue syndrome

Treatments for chronic fatigue syndrome (CFS) aim to help relieve the symptoms.

The treatments used depend on how CFS affects you. Early diagnosis, taking medication to control certain symptoms, and changing your lifestyle can all help.

CFS may last a long time, but treatment often helps improve the symptoms. Over time, many people get better and regain fully functioning lives.

Treatment programme

The National Institute for Health and Care Excellence (NICE) advises that an individual programme of treatment should be offered to you. This will aim to:

  • maintain and, if possible, increase your emotional and physical abilities
  • manage the physical and emotional effects of your symptoms 

You may be offered the treatments explained below, but remember that what works for one person may not work for you.

The benefits and risks of each treatment should be explained to you, as some treatments could make your symptoms worse.

Both you and the healthcare professional treating you will decide on your treatment programme. You have the right to refuse or withdraw from any treatment recommended for you.

If your symptoms continue to get worse for several days after trying a certain treatment or if your symptoms are particularly severe, contact the healthcare professional treating you. It may be necessary to amend your treatment programme.

Cognitive behavioural therapy

Cognitive behavioural therapy (CBT) is a type of therapy that can help you manage CFS by changing the way you think and behave. It’s often used as a treatment for a range of health conditions.

CBT aims to help reduce the severity of your symptoms and the distress associated with CFS. It works by breaking down overwhelming problems into smaller parts, and by breaking the negative cycle of interconnected thoughts, feelings, physical sensations and actions.

Ideally, your CBT therapist will have experience of dealing with CFS and treatment will be offered on a one-to-one basis. The treatment will be tailored to your needs and may include some of the following:

  • helping you accept your diagnosis
  • challenging feelings that could prevent your symptoms improving
  • trying to increase your sense of control over your symptoms

The use of CBT doesn’t mean CFS is considered to be a psychological condition. It’s often used as a treatment for a variety of long-term conditions, such as cancer and rheumatoid arthritis.

Graded exercise therapy

Graded exercise therapy (GET) is a structured exercise programme that aims to gradually increase how long you can carry out a physical activity.

This usually involves exercise that raises your heart rate, such as swimming or walking. You’ll have your own exercise programme adapted to your own physical capabilities.

GET should only be carried out by a trained specialist with experience of treating CFS and, if possible, should be offered on a one-to-one basis. After finding out what you can comfortably do already in the exercise (the baseline), you will gradually increase:

  • the length of time you do the exercise
  • the intensity of the exercise

As part of your exercise programme, you and your therapist will set goals, such as being able to walk to the shops or carry out some gardening. It may take weeks, months or even years for you to achieve these goals, but it’s very important not to exceed the exercise duration and intensity set for you.

Activity management

Activity management is another aspect of your treatment programme. It involves setting individual goals and gradually increasing your activity levels.

You may be asked to keep a diary of your current activity and rest periods to establish your baseline. Activities can then be gradually increased in a way you find manageable.


There’s no medication available to treat CFS specifically, but different medicines may be used to relieve some of the symptoms of the condition.

Over-the-counter painkillers can help ease any muscle pain, joint pain and headaches you may have. Stronger painkillers can also be prescribed by your GP, although they should only be used on a short-term basis.

If you have chronic (long-term) pain, you may be referred to a pain management clinic. There are about 300 of these across the UK, mostly located in hospitals.

Antidepressants can be useful for people with CFS who are in pain or having trouble sleeping. Amitriptyline is a low-dose tricyclic antidepressant that may be prescribed. 

It is not suitable for everyone – for example, it may not be suitable if you have a history of heart problems. It can also cause side effects such as a dry mouth, blurred vision, dizziness and drowsiness.

If you experience severe nausea as a result of CFS, you may benefit from a type of medication called an anti-emetic.

Lifestyle advice

As well as these treatments, you may find the lifestyle advice below helpful.


Pacing may be a useful way of controlling CFS symptoms. It involves balancing periods of activity with periods of rest.

It means not overdoing it or pushing yourself beyond your limits. If you do more than you are ready to, this could slow down your progress in the long term. Over time, you can gradually increase your periods of activity while making sure they’re balanced with periods of rest.

Learning how to make the most of your energy helps increase the amount you can do. However, you may need to arrange your daily and weekly activities around when you can be active and when you need to rest.

If you pace your activities at a level that’s right for you, rather than rushing to do as much as possible in a short space of time, you may be able to make steady progress.

However, there are some uncertainties about pacing. There’s insufficient evidence on the benefits or harm of this treatment, although it’s often recommended for CFS.

Other recommendations

The following recommendations may also help:

  • avoid stressful situations
  • avoid alcohol, caffeine, sugar and sweeteners
  • avoid any food and drink you’re sensitive to
  • eat small regular meals to help reduce any nausea
  • spend time relaxing
  • try not to sleep or nap excessively, as this doesn’t help and may make any sleeping problems worse


A relapse is when your symptoms get worse for some time, leaving you unable to function at the level you previously managed.

Relapses are a common part of CFS and can be caused by a number of factors, such as an infection or an unplanned activity. Sometimes there’s no clear cause.

The healthcare professionals treating you can help you manage your relapse by:

  • including more breaks with your current levels of activities
  • teaching you relaxation and breathing techniques
  • encouraging you to be optimistic about your recovery

Over time and with treatment, many people with CFS begin to show improvement.

Complementary therapies and supplements

Although some people with CFS have reported improvements from complementary therapies, there’s little evidence to suggest they’re effective for the condition. This means their use isn’t usually recommended for CFS.

There’s also insufficient evidence to recommend taking dietary supplements, such as vitamin B12 and vitamin C for CFS.