For decades, people suffering from chronic fatigue syndrome have struggled to convince doctors, employers, friends and even family members that they were not imagining their debilitating symptoms. Skeptics called the illness “yuppie flu” and “shirker syndrome.” But the syndrome is now finally gaining some official respect. The Centers for Disease Control and Prevention, which in 1999 acknowledged that it had diverted millions of dollars allocated by Congress for chronic fatigue syndrome research to other programs, has released studies that linked the condition to genetic mutations and abnormalities in gene expression involved in key physiological processes. The centers have also sponsored...