Although there is agreement on the genuine threat to health, happiness, and productivity posed by CFS/ME, various physicians' groups, researchers, and patient activists champion very different ideas regarding diagnostic criteria and favored treatments, resulting in ongoing controversy about nearly all aspects of the disorder. The name chronic fatigue syndrome is itself controversial, with some patient advocates and other authorities preferring terms such as myalgic encephalomyelitis ("ME" or "CFS/ME") and post-viral fatigue syndrome ("PVFS"), which imply specific underlying etiologies or pathologic processes.

While fatigue is a common symptom in many illnesses, CFS/ME is a multi-symptom disease and is relatively rare by comparison. Definitions require a number of features, the most common being severe mental and physical exhaustion which is "unrelieved by rest" and may be worsened by even trivial exertion. Most diagnostic criteria insist that the symptoms must be present for at least six months, and all insist on there being no other cause for them: i.e. the symptoms must not caused by other medical conditions such as diabetes, hypothyroidism or anemia. Click here for more information about CFS/ME symptoms.

It is unclear if these symptoms represent co-morbid conditions or are produced by the same underlying etiology as CFS itself. Some cases improve over time, and treatments (though none are universally accepted) bring a degree of improvement to many others, though resolution is rare.

CFS/ME occurs more often, but not exclusively, in women, possibly due to immunological factors or hormonal changes. CFS/ME is most easily diagnosed when formerly active adults become ill, and is most commonly diagnosed in young to middle aged adults, although it is also reported in children, adolescents and the elderly.

XMRV Retrovirus

Scientists have discovered a potential retroviral link to CFS/ME. Researchers from the Whittemore Peterson Institute (WPI), the National Cancer Institute (NCI), and the Cleveland Clinic, report this finding online in the Oct. 8, 2009, issue of Science.

"We now have evidence that a retrovirus named XMRV is frequently present in the blood of patients with CFS. This discovery could be a major step in the discovery of vital treatment options for millions of patients," said Judy Mikovits, PhD, director of research for WPI and leader of the team that discovered this association.

Researchers cautioned, however, that this finding shows there is an association between XMRV and CFS but does not prove that XMRV causes CFS.

"The discovery of XMRV in two major diseases, prostate cancer and now chronic fatigue syndrome, is very exciting. If cause-and-effect is established, there would be a new opportunity for prevention and treatment of these diseases," said Silverman, a co-author on the CFS paper.

Future research will look at prevalence among population groups, transmissibility, interaction with medications, impact of the duration of a CFS diagnosis on the activity of XMRV, and a wide variety of other factors. We are all interested in these results, as well as treatments studies to determine best management of infections.

• Frequently Asked Questions About XMRV
• Researchers Find Retroviral Link to CFS/ME

Narcolepsy

Researchers are aso looking into the possibility that CFS may be linked to Narcolepsy. In a recent article entitled, Sleep Quality and Psychological Adjustment in CFS, their conclusion was:

"Narcolepsy and CFS participants were very similar on psychological adjustment: both these groups had more psychological maladjustment than did control group participants."

In the book Sleep and Quality of Life in Clinical Medicine, written by Joris C. Verster, S. R. Pandi-Perumal, David L. Streiner, they say that:

"In a recent study evaluating the nature of CFS...we documented the presence and nature of sleep disorders in individuals with this diagnosis. Here, in a comparative investigation of CFS, narcolepsy, and healthy control participants, we found that approximately 60% of the sample of individuals with CFS had diagnosable primary sleep disorder such as sleep apnea/hypopnea syndrome and that almost everyone with CFS complained of nonrestorative sleep and/or insomnia characterized by difficulty initiating or maintaining sleep."

• Information about Narcolepsy

Possible Link to Endometriosis

In 2002, researchers at the National Institute of Child Health and Human Development (NICHD), the George Washington University, and the Endometriosis Association, conducted a study that was designed to analyze the association between having endometriosis and other immune system disorders.

They analyzed a survey conducted by the Endometriosis Association, in which 3,680 women stated they had been surgically diagnosed with endometriosis, to see how many would go on to be diagnosed with other types of disorders. What they discovered is that women with this condition were significantly more likely to have other autoimmune disorders.

In fact, they found the women were over one hundred times more likely to develop chronic fatigue syndrome (CFS), and more than twice as likely to experience fibromyalgia than the general American female population. In addition, of the more than 20 percent who had more than one other disease, 31 percent of those had either fibromyalgia or CFS.

Although the researchers were unable to confirm why these conditions appear to be related, they are now encouraging doctors to consider endometriosis when evaluating their patients for either CFS or fibromyalgia.

In the journal European Society of Human Reproduction and Embryology researchers examined whether the prevalence of autoimmune, chronic pain and fatigue and atopic disorders is higher in women with endometriosis than in the general female population.

A cross-sectional survey was conducted in 1998 by the Endometriosis Association of 3680 USA members with surgically diagnosed endometriosis. Almost all responders had pain (99%), and many reported infertility (41%). Compared with published rates in the general USA female population, women with endometriosis had higher rates of:

• hypothyroidism (9.6 versus 1.5%, P < 0.0001)
• fibromyalgia (5.9 versus 3.4%, P < 0.0001)
• chronic fatigue syndrome (4.6 versus 0.03%, P < 0.0001)
• rheumatoid arthritis (1.8 versus 1.2%, P = 0.001)
• systemic lupus erythematosus (0.8 versus 0.04%, P < 0.0001)
• Sjögren's syndrome (0.6 versus 0.03%, P < 0.0001)
• multiple sclerosis (0.5 versus 0.07%, P < 0.0001)

But not hyperthyroidism or diabetes. Allergies and asthma were more common among women with endometriosis alone (61%, P < 0.001 and 12%, P < 0.001 respectively) and highest in those with fibromyalgia or chronic fatigue syndrome (88%, P < 0.001 and 25%, P < 0.001 respectively) than in the USA female population (18%, P < 0.001 and 5%, P < 0.001 respectively).

They concluded that hypothyroidism, fibromyalgia, chronic fatigue syndrome, autoimmune diseases, allergies and asthma are all significantly more common in women with endometriosis than in women in the general USA population.

A lack of information and awareness has led to many patients being stigmatized as hypochondriac or lazy. The Centers for Disease Control & Prevention have now recognized CFS/ME as a serious illness and have recently launched a campaign to raise public and medical awareness about it. The American Medical Association (AMA), the World Health Organization (WHO), and the National Institutes of Health (NIH) are among those who have accepted CFS/ME as a legitimate physical illness and a major cause of disability.

According to The Center for Disease Control (CDC), CFS/ME affects more than 1 million people in the United States. According to The University of Maryland Medical Center, four in every 1000 Americans are affected by CFS/ME. CFS patients are denied insurance benefits and do not seek medical treatment.

This illness strikes more people in the United States than multiple sclerosis, lupus, lung cancer or ovarian cancer. According to a large 1999 US study, the highest rates of CFS/ME were found among women in general. Chronic fatigue is most often experienced by individuals 40 to 50 years old; it is least prevalent in people under 29 or over 60. This disorder, however, occurs in both sexes and at all ages and in all racial and ethnic groups.

Researchers continue to explore possible causes and risk factors for CFS/ME. Many questions remain, but there are some characteristics that may help indicate who is most at risk for CFS/ME:

• CFS/ME occurs four times more frequently in women than in men, although people of either gender can develop the disease.


• The illness occurs most often in people in their 40s and 50s, but people of all ages can get CFS/ME.


• Children and adolescents are not immune to its effects. Most studies indicate that girls are more apt to develop CFS/ME than boys, although one study found the incidence of the syndrome to be equal. According to a 1999 study, half of the children and adolescents with CFS/ME also suffer psychiatric disorders, primarily anxiety, and also depression.


• CFS/ME occurs in all ethnic and racial groups, and in countries around the world. Research indicates that CFS/ME is at least as common among African Americans and Hispanics as it is among Caucasians.


• People of all income levels can develop CFS/ME.


• CFS/ME is sometimes seen in members of the same family, but there's no evidence that it's contagious. Instead, there may be a familial or genetic link. Further research is needed to explore this.