Chronic Fatigue Syndrome Not Fully Understood

The researchers conducted an extensive review of recent studies addressing the definition, prevalence, prognosis, causes, and treatment of CFS. Their research appears in the current issue (Vol. 21, No. 3) of Annals of Behavioral Medicine.

"CFS is a frustrating illness for its sufferers, their physicians and allied health care professionals, and the scientists studying it," said Susan K. Johnson, PhD, head of the study. "Although CFS has been the focus of increased research efforts in the past decade, a fractious lack of consensus exists on how it should be defined, and insufficient progress has been made toward understanding its etiology and prognosis, and toward designing effective treatments."

Definitions of CFS have evolved over time. According to a 1994 joint Centers for Disease Control and Prevention/National Institutes of Health working group, CFS involves six-month’s duration of persistent, unexplained fatigue combined with other symptoms such as cognitive impairment, sore throat, tender neck or lymph nodes, muscle pain, joint paint, unusual headache, unrefreshing sleep, and more than 24 hours of post-exertional malaise.

Just as definitions of CFS vary, the literature review also showed that estimates of its prevalence also vary. Studies in the United States have estimated that as many as 380 out of every 100,000 people suffer from the syndrome, which most often afflicts middle-aged women.

The researchers also note that debate continues as to whether CFS is an emotional disorder or an organic disease. Some researchers have postulated that CFS is a manifestation of a psychiatric condition such as hypochondriasis, somatization disorder, or forms of depression, although patterns of CFS generally differ from those of depression. Other scientists contend that CFS is a medical illness resulting from a virus or an infection or from neuroendocrine abnormalities.

The research was supported in part by the National Institutes of Health.