Return to Chronic Fatigue Syndrome - Causes

If you think you have chronic fatigue syndrome (CFS), don't diagnose yourself. See a doctor. Profound fatigue can be caused by many other medical conditions that may be life-threatening if not properly diagnosed and treated.

What percent have CFS?

According to the National Institute for Allergy and Infectious Diseases (NIAID), about 25 percent of all patients who see a general practitioner complain of prolonged fatigue, but research suggests only a small fraction of these patients meet the criteria for CFS.

CFS is a diagnosis of exclusion. The following medical conditions that can cause persistent fatigue need to be ruled out before a diagnosis of CFS can be established.

Conditions that can cause persistent fatigue:

• Hypothyroidism

• Sleep apnea

• Narcolepsy

• Unresolved hepatitis B or C

• Alcohol or substance abuse

• Severe obesity and sleep apnea

• Side effects of certain medications

• Lupus

• Rheumatoid arthritis

• Multiple sclerosis

• Cancer

• Major depressive disorder

• Bipolar disorder

• Anorexia nervosa

• Bulimia nervosa

• Schizophrenia

• Dementia

• HIV/AIDS

• Anemia

• Mononucleosis

Related Articles Treating Chronic Fatigue Syndrome Chronic Fatigue Syndrome Who Gets Chronic Fatigue Syndrome? Diagnosing Chronic Fatigue Syndrome Additional Resources for Chronic Fatigue Syndrome Asleep at the Wheel? The Problem of Excessive Sleepiness

External Sources National Library of Medicine of the National Institutes of Health. Chronic Fatigue Syndrome. Accessed May 15, 2007. CFIDS Association of America. About CFIDS. Accessed May 15, 2007. American Association for Chronic Fatigue Syndrome. Case Definitions. Accessed May 15, 2007.

This article was reviewed and updated June 2007.