Syndrome rarer than reports claim.

Chronic fatigue syndrome (CFS) may be in the news more than in the general population. Hyped as the epidemic of the 1990s, it results in debilitating fatigue and neuromuscular and neuropsychological symptoms. The syndrome is said to occur more frequently in women than men and has been linked to viral infections, immune deficiency, psychiatric disorders, and even allergies. Its cause and cure remain unknown.

The Centers for Disease Control lists major symptoms as persistent and debilitating fatigue of six months or more that results in a significant reduction in routine activities. It defines minor symptoms as mild fever, sore throat, painful lymph nodes, general muscle weakness and discomfort, prolonged fatigue, headache, joint pain, and neuropsychological complaints such as transient visual problems, forgetfulness, slow thinking, depressed mood, and sleep disturbances.

Rumi K. Price, research instructor of epidemiology in psychiatry, and Carol S. North, assistant professor of psychiatry, Washington University School of Medicine, found only one person in their study of more than 13,500 people who met the diagnosis for chronic fatigue syndrome. Less than one-quarter of the study population had experienced fatigue lasting two weeks or more, and, in about half of that group, it was explained by physical illness or medication. The...