Today some people will not step outside, fly on a plane, go to work or even act on a hot stock tip. It's Friday the 13th -- a day filled with mild dread for some and such fear for others that shuttering themselves indoors seems completely reasonable.
"And they usually don't ask for treatment," said Dr. Donald Dossey, a psychotherapist and founder of the Stress Management Center and Phobia Institute in Asheville, N.C. "They are either too ashamed or feel like it's fleeting."
Most people who believe the day is unlucky offer no explanation. Like all other phobias, people fear Friday the 13th for its own sake, according to Dossey, author of "Holiday Folklore, Phobias and Fun: Mythical Origins, Scientific Treatments and Superstitious 'Cures' " and "Keying: The Power of Positive Feelings: Overcoming Fears, Phobias and Stress."
He said as many as 21 million people fear the date.
"The origin of it is so deeply ingrained in our culture that there is some kind of feeling of justification for people who are stricken with the fear," Dossey said.
It's estimated that between $800 million and $900 million is lost in business each Friday the 13th because people won't travel, go to work and tend to business in general.
The origins of the fear stem from several different stories combining the idea that 13 is an unlucky number and Friday an unlucky day. One of the origins is believed to come from Christianity. There were 13 people at the Last Supper and Christ was crucified on a Friday. Also, Judas, the apostle who betrayed Jesus, was the 13th guest at the Last Supper. In ancient Rome, witches reportedly gathered in groups of 12. The 13th was believed to be the devil.
Still, some think 13 owes its bad reputation originally to Loki, the Norse god of evil, who started a riot when he crashed a banquet at Valhalla attended by 12 gods. Once there, Loki (who then became the 13th god at the banquet) arranged for Hoder, the blind god of darkness, to shoot Balder the Beautiful, the god of joy and gladness, with a mistletoe-tipped arrow.
"Balder died and the whole Earth got dark. It was a bad, unlucky day," said Dossey.
Whatever its ominous origin, the fear of the number 13 is pervasive whether it just elicits a minor sense of doom over your day or a debilitating fear.
"Fear of Friday the 13th is like any other fear," said Seymour Segnit, who founded Change That's Right Now, which uses neuro-linguistic programming and time-line therapy to help people with phobias. Those processes allow people to make changes at an unconscious level to feel back in control.
Segnit says CTRN's Web site gets more clicks on and near the date by people looking for help in coping with the fear.
"It's one of those phobias that the world doesn't take seriously," Segnit said. "People will make fun of it, but for anyone who has it, it's not funny at all."
For some, just seeing the date on the calendar starts the panic. For others, hearing the date said out loud can cause a cold sweat, Segnit said. But there are some things they can do.
"We have treated many people, mostly by phone only because it's problematic for a lot of people to leave their homes on that day," Dossey said.
Dossey says a key to controlling any phobia is to first utilize the power of positive thinking.
"If a person can think about things that make them feel calm and relaxed they can control their mind and their feelings," he said.