What is Chronic Fatigue Syndrome?

Chronic fatigue syndrome is a condition that leads to symptoms of persistent fatigue that do not resolve after rest or sleep.

The medical term used for this condition is myalgic encephalomyelitis and chronic fatigue syndrome is also know of as ME. The term myalgic encephalomyelitis can be broken up into “myo” meaning muscle, “algia” meaning pain and encephalomyelitis meaning inflammation of the brain and spinal cord.

Chronic fatigue syndrome is an under-diagnosed condition that can seriously impact on normal day-to-day living and even cause disability, although many people recover over time, especially young people and children.

Chronic fatigue syndrome may affect any individual but is more common in women than in men and in those aged between 20 and 50 years. Among children, the condition usually develops between the ages of 13 and 15. 

Symptoms and course of the disease

In three quarters of all patients with this condition, the symptoms are mild to moderate. In the case of mild symptoms, patients can usually take care of themselves but may take time off from work to rest. Moderate symptoms can cause mobility problems and disrupted sleep patterns. In severe cases, individuals may be able to carry out the most simple of tasks such as washing their face but mobility is significantly reduced and concentration is diminished.

Cause of chronic fatigue syndrome

The exact cause of this condition is not known but some studies have indicated that viral infection, immune disorder, hormonal imbalance or psychiatric issues such as emotional trauma may play a role.


According to criteria form the National Institute of Health and Clinical Excellence (NICE), the fatigue criteria that need to be fulfilled for a diagnosis of chronic fatigue syndrome include:

  • No previous history, so new onset
  • Persistent
  • Unexplained by other conditions
  • Substantially impacts on activity level
  • Feels worse after physical activity

In addition, one or more of the following criteria need to be met:

  • Sleeping difficulty or insomnia
  • Difficulty thinking or concentrating
  • Headache
  • Joint pain
  • Sore throat
  • Painful lymph nodes
  • Worsening of symptoms after activity
  • General malaise or flu-like symptoms
  • Dizziness
  • Nausea
  • Heart palpitations


Chronic fatigue syndrome cannot be cured and treatment is aimed at reducing symptoms. Some of the most common treatments used are cognitive behavioural therapy (CBT), graded exercise therapy and medications that alleviate pain, sleep disturbances and nausea.

Further Reading

Last Updated: Jul 7, 2023

Dr. Ananya Mandal

Written by

Dr. Ananya Mandal

Dr. Ananya Mandal is a doctor by profession, lecturer by vocation and a medical writer by passion. She specialized in Clinical Pharmacology after her bachelor's (MBBS). For her, health communication is not just writing complicated reviews for professionals but making medical knowledge understandable and available to the general public as well.


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