Chronic fatigue syndrome was defined originally by Holmes, Kaplan, Gantz, et al. (1988) as chronic or recurrent debilitating fatigue, which is aggravated after exertion and lasts for at least six months. Associated features may include sore throat, headache, muscle pain, joint pain, decreased memory, poor concentration, confusion, and depression. Patients may feel that they have fever, and lymph node tenderness may be present. Typically, physical examination and laboratory investigations are normal. There are no accurate data with regard to the prevalence of chronic fatigue syndrome in the general population, however, it is more common in women and has its onset following a "flulike illness" (Buchwald & Garrity, 1994).