Chronic fatigue syndrome refers to long-standing severe and disabling fatigue without a proven physical or psychologic cause and without objective abnormalities found on physical examination or laboratory testing.
Unexplained fatigue lasts for 6 consecutive months or longer.
Sometimes symptoms begin during or after an illness that resembles a viral infection.
Treatments include relieving symptoms, cognitive-behavioral therapy, and graded exercise.
Although as many as 25% of people report being chronically fatigued (see Fatigue), only 0.5% of people (1 in 200) have chronic fatigue syndrome (CFS). Chronic fatigue syndrome affects people primarily between the ages of 20 and 50 and is more common among young and middle-aged women than men, although it occurs in people of all ages, including children. People with chronic fatigue syndrome have real and often disabling symptoms. Chronic fatigue syndrome is not the same as pretending to have symptoms (a disorder known as malingering).