If you expect bad luck to break out on Friday the 13th, you're hardly alone. According to London's Daily Mirror, more than 60 million people worldwide claim to be affected by a fear of Friday the 13th. Some people may refuse to get on a plane, get behind the wheel of a car or go to work.

Fear of Friday the 13th has a couple of rather cumbersome names attached to it: friggatriskaidekaphobia or paraskevidekatriaphobia. And there is also the fear of the number 13 itself, triskaidekaphobia.

The origins of the inauspicious reputation surrounding Friday the 13th are murky, but there are various theories. Some Christians believe that Judas was the 13th guest at the Last Supper and betrayed Jesus, who was later crucified on a Friday. Others believe the phobia originated when King Philip IV of France arrested and tortured the Knights Templar on Friday, Oct. 13, 1307.

For many people, fear is an element of daily life, with cases ranging from mild to crippling. Some scientists say phobias are indicative of the evolutionary tendency to protect ourselves from dangerous situations. They think that many phobia-related panic attacks are just exaggerated episodes of otherwise reasonable fears.

While some fears are more easily rationalized than others, they can all be torturous for those who suffer from them. Here are some common phobias:

Triskaidekaphobia:  Fear of the number 13 is one of the most commonly reported fears.

Aerophobia: After Sept. 11, 2001, attacks, fear of flying came to the fore, but it's been around as long as commercial flight. Help for the condition ranges from education and guidance to support groups, psychiatric counselling, hypnosis and psychotropic medication.

Mysophobia: The fear of germs can last much longer than an outbreak of disease. Sometimes associated with obsessive compulsive disorder and characterized by handwashing, brushing your teeth and frequent bathing, this anxiety can lead sufferers into an endless cycle of sanitization.

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Driving phobias include avoidance of left turns and fears of intersections and freeways. (Associated Press)

Fear of driving: Driving phobias range from avoidance of left turns and parallel parking to fears of intersections and freeways. Some people who suffer from this anxiety are forced to give up driving entirely.

Agoraphobia: The fear of leaving secure spaces is a condition that can cause elevated pulse levels, tightness in the chest and sweating. Many sufferers become confined to a tiny geographic radius. Others are completely unable to leave the house. Treatment often includes counselling and medication.

Claustrophobia: The fear of being in enclosed or confined spaces keeps sufferers out of elevators, trains, aircraft and crowds. This disorder can be particularly serious since sufferers can't always escape the cause of their panic. Cognitive therapy and antidepressant medication are commonly used to treat the condition.

Coulrophobia: Stephen King's It and clown-costumed killer John Wayne Gacy pulled the fear of clowns out of the shadows. But the muscular stiffening, sweating and goose bumps caused by the sight of a clown can be treated with relaxation and breathing techniques.

Necrophobia: Fear of death often occurs in conjunction with other fears. Necrophobia also includes the fear of dead things.

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Arachnophobia refers specifically to aversions to spiders. Fear of other insects is called entomophobia. (Associated Press)

Arachnophobia: Although it has been associated with crawling insects in general, arachnophobia refers specifically to aversions to spiders. Fear of other insects is called entomophobia. But, if it's the itching that "bugs" you, it's called acarophobia.

Acrophobia: Sometimes associated with aerophobia, acrophobics don't need to be in an airplane to experience their jitters. You won't find sufferers of this anxiety in tall buildings or riding roller-coasters. Some of them aren't even able to climb a flight of stairs.

Zoophobia: This is the fear of animals. There exist more specific fears of cats, dogs, reptiles and other wild things, but zoophobics prefer humans.

Some fears aren't truly phobias in the clinical sense of the word, but the result of other factors. Aversions such as xenophobia (fear of strangers and the unknown), homophobia (fear of homosexuality), and islamophobia (fear of Islam) are terms that have taken on a popularized meaning and actually have no medical pathology.