But infectious agents may not be the only culprits. Peter Rowe, a pediatrician and director of the chronic fatigue syndrome clinic at Johns Hopkins Children’s Center, has documented that some young people who developed the syndrome also have a disorder called neurally mediated hypotension; their blood pressure plunges after they’ve been standing for several minutes, leading to dizziness, weakness and, over time, exhaustion. Other medical researchers have failed to find the same link between bouts of low blood pressure and chronic fatigue syndrome, but Rowe remains convinced it’s a factor in some cases and says he has given such patients blood-pressure-regulating drugs with good effect. Likewise, Rowe and other researchers have argued that a heart rate abnormality, postural tachycardia syndrome, in which a racing heart causes light-headedness, may also be involved in chronic fatigue syndrome.
Even though the disorder has been recognized only fairly recently as a clinical entity—the CDC officially defined chronic fatigue syndrome in 1988—it probably isn’t new to humanity. Physicians and historians of medicine say it closely resembles neurasthenia, a so-called nervous exhaustion that was one of the most commonly diagnosed conditions in the United States and Europe in the second half of the 19th century.
“If you read the descriptions of neurasthenia in 1880 in journals, textbooks and the diaries and letters of patients, you would be in no doubt that what they’re describing is chronic fatigue syndrome,” says Dr. Simon Wessely, a London psychiatrist and coauthor of the 1998 book Chronic Fatigue and its Syndromes. But neurasthenia, originally thought to be caused by infection or overwork, fell out of favor as a diagnosis before World War I, largely because doctors failed to find a concrete reason for it.
Historically, says DePaul University psychologist Leonard Jason, physicians have treated many mysterious chronic illnesses as psychological problems. For example, some experts once thought multiple sclerosis was caused by “stress linked to oedipal fantasies,” he says. “But later, with the development of sophisticated imaging technologies, researchers showed clearly that MS is a neurological disease that has a physical cause.” Similarly, he predicts, advances will reveal that “physical causes also underlie most cases of CFS.”
One of the most surprising findings is that chronic fatigue syndrome appears to be 100 times more common than many experts previously believed. In a study led by DePaul’s Jason, researchers surveyed some 18,000 people in Chicago by phone, then gave medical exams to respondents who reported chronic fatigue symptoms: 4 out of every 1,000 people surveyed had the affliction, leading to an estimate of more than 800,000 cases nationwide. And contrary to the stereotype of the disorder as an affliction of well-to-do young whites—“the Yuppie flu,” it was once dismissively called—the researchers found that the syndrome was most prevalent among the minorities and lower-income people surveyed. Also, nearly two out of three cases had no prior history of psychiatric problems, contradicting the widespread view that chronic fatigue syndrome is really just a symptom of an underlying mood disorder such as depression or anxiety. A notable feature of the disorder’s prevalence is its pronounced sex bias. More than two out of three chronic fatigue patients are women. Researchers don’t know why.