Medical professionals have been reluctant to acknowledge chronic fatigue syndrome (CFS) as an actual condition. Instances of incapacitating fatigue were foreign to them, and so they had no idea how to isolate the cause — let alone suggest treatment. But a new report from the Institute of Medicine (IOM) is set to change that.

The IOM was tasked by the Department of Health and Human Services, the National Institutes of Health, the Agency for Healthcare Research and Quality, the Centers for Disease Control and Prevention, the Food and Drug Administration, and the Social Security Administration to convene an expert committee to examine the evidence base for CFS. As a result of their examination, the IOM concluded CFS is, in fact, a serious, chronic condition, profoundly affecting between 836,000 and 2.5 million American patients' lives. They just disagree with its current name.

Now, IOM classifies CFS as systemic exertion intolerance disease (SEID). The new name better identifies the core characteristic of the condition, which is that exertion of any kind can adversely affect patients. An alternative name for CFS — “myalgic encephalomyelitis” — suggested myalgia, or muscle pain, was at the core of the disease; this is not the case. Other names in the past, according to NPR, have included epidemic neuromyasthenia and Royal Free Disease.

After the condition's name change, the IOM proposed diagnostic criteria. In order for patients to be diagnosed, they'll be required to exhibit the following symptoms: “a substantial reduction or impairment in the ability to engage in pre-illness levels of occupational, education, social, or personal activities that persist for more than six months; post-exertional malaise; and unrefreshing sleep.” Additionally, patients will need to exhibit one of two manifestations: cognitive impairment or orthostatic intolerance.

Since the diagnostic criteria’s effectiveness is contingent upon health care providers actually using it, the IOM outlined a nationwide strategy for providers, schools, employers, and patient groups. Ultimately though, Ellen Wright Clayton of Vanderbilt University, IOM’s committee chair, told The Washington Post this was a way to put to rest that CFS is all in a patient’s head.

However, despite the acknowledgement and criteria changes, challenges remain. Experts still don't know what causes the condition (though it’s believed to be triggered by certain infections). Plus, the efficacy of treatments in place has also yet to be determined. Generally, there’s a lack of research that offers insight to how this type of fatigue develops and progresses.

"Change is not easy in any system, especially complex systems," Dr. Lucina Bateman, of the IOM committee and fatigue specialty clinic in Salt Lake City, told NPR. "But I think we have about as good a foundation as we possibly could have to jump-start this process."

Source: Beyond Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Redefining an Illness. The National Academics Press, 2015.