Abstract:
Chronic fatigue syndrome, previously known as chronic mononucleosis or post-infectious fatigue, is a poorly understood illness characterized by chronic debilitating fatigue, recurrent flu-like symptoms, and few clinical or laboratory abnormalities. Attention was briefly focused on the Epstein-Barr virus (EBV) as a causal agent, but that hypothesis is now in serious doubt. While a significant incidence of psychiatric illness has been demonstrated among patients with the chronic fatigue syndrome, there is also evidence of subtle immune system abnormalities, leading some researchers to postulate a multi-factorial psycho-immune cause.
Source: Turgeon SA. Chronic fatigue syndrome: review of the literature. Can Fam Physician. 1989 Oct;35:2061-5. http://www.ncbi.nlm.nih.gov/pubmed/21249084
Note: You can read the full article here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2280912/