If you love scary movies, then you have undoubtedly seen any or all of the films in the Jason Voorhees “Friday the 13th” series. However, if you are like me, and the mere thought of a horror movie causes nightmares, then you probably fear Friday the 13th for less cinematic reasons. This fear is one of the most widespread superstitions in contemporary society. Known as “paraskevidekatriaphobia,” the irrational fear of Friday the 13th has its origins in ancient mythology and has nothing to do with a hockey mask-wearing psychopathic killer.

Origins:
The number 13 and the day Friday are both considered unlucky for separate reasons, but when they fall on the same day this bad luck is amplified.

- 13’s unluckiness is often traced to the Norse legend of a gathering of 12 gods at their heaven, Valhalla, when an uninvited 13th guest showed up and arranged the assassination of the god of happiness and light.

-The Christian tradition also negatively associates the number 13 with Judas, the 13th guest at the Last Supper who betrayed Jesus.

-Numerologists consider 12 to be a “complete” number, the addition of one to make 13 results in a restless and incomplete number. There are 12 months of the year, 12 gods of Olympus, 12 tribes of Israel and 12 apostles of Jesus. Alternatively, there are 13 witches in a coven, and those people with 13 letters in their name have the devil’s luck, i.e. Jeffrey Dahmer, Jack the Ripper and Charles Manson.

-Friday’s bad luck is primarily associated with Christianity because it was on this day that Jesus was crucified, Abel was killed by Cain and it is thought that the fall of Eve also occurred on a Friday.

Today:
Evidence of the fears surrounding the number 13 by itself and Friday the 13th are prevalent in many areas of society:

-80 percent of high-rise buildings do not have a 13th floor, many hospitals and hotels do not have No. 13 rooms and many airports skip 13 in their gate-numbering systems.

-In Florence, Italy, houses between 12 and 14 are referred to as “12 and a half.”

-According to Dr. Donald Dossey, a psychotherapist specializing in phobias, nearly 21 million Americans suffer from paraskevidekatriaphobia.