Chronic fatigue syndrome is a chronic illness characterized by symptoms such as severe fatigue, difficulty thinking clearly, and pain. Although CFS is estimated to be fairly common (some sources suggest it affects 1 in 100 people), many individuals remain undiagnosed due to the condition’s unclear cause, varying symptoms, and inadequate treatments.[1][2]
What is chronic fatigue syndrome?
Written by:
Fact-checked
by:
•Last Updated: May 16, 2025
Chronic fatigue syndrome is a chronic illness marked by severe fatigue, cognitive difficulties, and pain. It is estimated to affect approximately 1 in 100 people, but many people remain undiagnosed due to its unclear cause and varying symptoms.