The Centers for Disease Control and Prevention first investigated chronic fatigue syndrome in the mid-1980s, when a few hundred people in Nevada suddenly got symptoms much like mine. A couple of doctors documented physiological factors, including abnormal MRI scans and immune problems, and noted that the malady fit the profile of myalgic encephalomyelitis, an illness that had cropped up sporadically for decades.

CDC investigators created a broad definition for the illness, which did not involve MRI scans or findings about the immune system. The diagnostic criteria included at least six months of fatigue along with other subjective symptoms such as sore throat, swollen lymph nodes and brain fog. They called the illness “chronic fatigue syndrome” and subsumed myalgic encephalomyelitis within it. (The agency now often calls the illness ME/CFS).

In 2005, the CDC broadened the definition further, requiring only low levels of symptoms other than fatigue, and the number of patients who qualified for the diagnosis increased by six to 10 times.

Researchers and clinicians specializing in the disease, in the meantime, created a far more precise definition, requiring post-exertional malaise — a severe increase of symptoms after exercise — along with abnormalities in neuroendocrine and immune functioning, and in the autonomic nervous system, which controls respiration, blood pressure, digestion and perspiration. But without official endorsement, it has not become universally accepted.

Other CDC actions have worsened the muddle. For example, the agency recommends that CFS patients gradually increase exercise, suggesting that this will restore bed-bound patients to daily functioning, though even the most encouraging studies show that to be unrealistic.

The CDC also recommends cognitive behavioral therapy (a form of psychotherapy) but almost none of the treatments that enabled me to work part time again.

With confusing definitions and weak treatment recommendations, it’s hardly surprising that most general practitioners recommend no treatments for CFS other than some symptomatic care along with psychotherapy and exercise.