Chronic fatigue syndrome (CFS) is the most common name used to specify a medical disorder or group of disorders generally defined by persistent fatigue accompanied by other specific symptoms for a minimum of six months, not due to ongoing exertion, not substantially relieved by rest, nor caused by other medical conditions. The disorder may also be referred to as myalgic encephalomyelitis (ME), post-viral fatigue syndrome (PVFS), or several other terms. Although classified by the World Health Organization under Diseases of the nervous system, the etiology (cause or origin) of CFS is unknown, and multiple psychological and physiological factors may contribute to the development and maintenance of symptoms...