Chronic fatigue syndrome's defining characteristic is a persistent deep fatigue, similar to what other people feel when they're seriously ill or sleep deprived. In people with chronic fatigue syndrome, however, sleep doesn't relieve fatigue as it does in healthy people.
People with chronic fatigue syndrome also have other symptoms, including severe pain, cognitive problems such as memory loss and confusion, and post-exertional malaise. Post-exertional malaise causes intense fatigue, pain and muscle weakness for up to 48 hours following exercise or other forms of exertion.
Things like injury, illness and stress (emotional or physical) can make symptoms worse. Some people have specific triggers (things that increase symptoms), such as foods or chemicals.
People from every culture and socioeconomic level get chronic fatigue syndrome. It's most common in women, but men and children can come down with it as well.
Chronic fatigue syndrome, by different names, dates back to the 1700s. Throughout the centuries, it's been falsely attributed to various causes and is only now beginning to be understood by medical science.
More than 1 million people in the U.S. are known to have chronic fatigue syndrome, but some experts and advocates estimate that many people are undiagnosed and that the number is actually much higher. Many people with chronic fatigue syndrome are too disabled to work.
The Social Security Administration does recognize chronic fatigue syndrome as a potentially disabling condition. However, having a disability claim approved is a long and difficult process that can be complicated by the ambiguous nature of chronic fatigue syndrome symptoms and the lack of a diagnostic test.
Chronic fatigue syndrome (CFS) goes by several names, including chronic fatigue and immune dysfunction syndrome (CFIDS), myalgic encephalomyelitis (ME), and ME/CFS. Currently, advocacy groups in the U.S. are working to change the name officially to the acronym ME/CFS, with the ME standing for either myalgic encephalomyelitis or myalgic encephalopathy.
So far, no test can accurately diagnose chronic fatigue syndrome. Doctors do need to rule out numerous conditions with similar symptoms before diagnosing chronic fatigue syndrome.
Diagnostic criteria include unexplained, persistent fatigue that's lasted for at least 6 months, and at least four of several other symptoms, including impaired memory or concentration, post-exertional malaise, unrefreshing sleep, muscle pain and others.
The FDA has not approved any drugs for chronic fatigue syndrome. An FDA decision on the anti-viral drug Ampligen is expected in 2009.
No medical specialty has "claimed" chronic fatigue syndrome, which can make it difficult to find a doctor knowledgeable about diagnosing and treating it.
People with chronic fatigue syndrome sometimes see massage therapists, chiropractors, physical therapists and other complementary and alternative-medicine practitioners. They may also see a psychiatrist or psychologist to deal with the difficulties of a debilitating condition and possibly for depression.
Depression is common in people with chronic fatigue syndrome, as it is in debilitating pain conditions overall. Chronic fatigue syndrome, however, is not a psychiatric condition.
Researchers don't yet know the exact cause of chronic fatigue syndrome, but many experts now believe it's triggered by genetic mutations combined with exposure to certain viruses or toxins.
Chronic fatigue syndrome is officially classified as a syndrome because it's a collection of signs and symptoms that are known to occur together, but without a known pathology.
Some researchers believe that there have been outbreaks of chronic fatigue syndrome, but other say we have insufficient evidence to prove any such outbreaks.