When anxiety hits Betty Simpson, her mind becomes a sort of Daytona 500, where thoughts, worries and fears careen around in a blinding blur.
Her hands clutch the steering wheel so tightly her knuckles turn white. Or, trying to outrace her repetitious thoughts, the 42-year-old social worker from Rocky Hill, Conn., loads the dishwasher and starts her laundry, only to ditch both chores and go for a bike ride.
"When you go over the edge, you can't concentrate, you can't focus, your memory goes," said Simpson. "You can't shake the feeling that something bad is about to happen if you don't keep going."
Simpson is one of the estimated 19 million American adults who suffer from an anxiety disorder, a diverse group of ailments sculpted from the primal emotion of fear. As many as one in four people will experience some type of anxiety disorder in their lifetimes.
Science and the experiences of people like Simpson shed light on reasons why we fear -- and how events can turn an emotion that was designed by nature to preserve our lives into a devouring obsession.
Fear is perhaps the oldest of all emotions. Its ancient genesis can be seen in the recoil of a single-celled organism from a dangerous stimulus.
While a human may inherit a propensity for anxiety, the form it takes seems to be shaped primarily by the environment, said William Clark, professor emeritus at the University of California, Los Angeles.
Simpson, for instance, suffers from generalized anxiety disorder, characterized by an excessive concern about nonthreatening events or situations. In the aftermath of the Sept. 11 attacks, many Americans have reported feeling the edginess, sleeplessness and remoteness from family and friends that are classic symptoms of generalized anxiety.
Many people with generalized anxiety disorder also experience depression, which scientists are now recognizing as a closely related condition, and panic disorder, which is in essence a paralyzing fear of fear itself.
Clark and other scientists believe that evolution branded fearfulness deep into the genome of our species. Those who lacked the sufficient fear response tended to perish, leaving the more timid and cautious to pass on their genes to generations to come.
"The question is, if fear is such a valuable adaptation, why does it feel so bad?" said Ned Kalin, professor of psychiatry at the University of Wisconsin. "The answer is that physical and psychological pain orients us to take care of the problem."
