What is (are) Chronic fatigue syndrome ?
Chronic fatigue syndrome, also known as systemic exertion intolerance disease, is a condition that causes extreme, long-lasting fatigue which can limit the ability to participate in ordinary, daily activities.  It generally occurs in young adults between the ages of 20 and 40 and is twice as common in women. The main symptom is disabling fatigue that does not improve with rest. Other signs and symptoms may include muscle pain; joint pain; concentration and memory problems; headaches; sleep problems; fever; sore throat; and/or tender lymph nodes. The cause of chronic fatigue syndrome is not known yet. Some researchers have proposed that this condition is caused by viral infections or by immunological, hormonal or mental or psychiatric problems, but none have been proved. It is also believed that there may be a genetic predisposition for this condition and stress-related events act as triggers. Because the symptoms are similar to many conditions that need to be ruled out, the diagnosis make take some time to be made and patients are frequently misunderstood. Those who are affected are typically highly functioning individuals who are "struck down" with this disease. There is still no cure for this condition but there are several clinical trials. Current treatment consists of cognitive and/or behavioral therapy and focuses on improving symptoms and may include medications to treat pain, sleep disorders and other associated problems. There is significant controversy and debate in the medical literature about the relationship between myalgic encephalomyelitis and chronic fatigue syndrome. Unfortunately there is no consensus on nomenclature or classification for these disorders, and different countries, organizations, and researchers continue to use different names to describe these conditions. Until a global consensus is reached on how to name and classify these disorders, confusion will persist.