Phobos, the Greek god who was called upon to frighten one's enemies, had his likeness painted on masks and shields for exactly that purpose. Over time, his name evolved into "phobia" which came to mean fear or panic.

The word first appeared medically some 2000 years ago in Rome, when hydrophobia was used to describe a symptom of rabies. Phobic behaviors were referred to in medical literature long before that, however. Hippocrates wrote of at least two phobics: one who was "beset by terror" whenever he heard a flute, and another who was not able to walk next to "even the shallowest of ditches."

In 1871, three men who feared the public were labeled agoraphobics and were told to seek companionship, drink alcohol and use a cane.

Over the years, phobia has been added to Latin and Greek words for objects and situations to name numerous fears. Some of the more unusual ones are taphephobia (fear of being buried alive), siderodromophobia (fear of railways), anthophobia (flowers), and triskaidekaphobia (fear of the number 13). Some of the more common are: ailurophobia (fear of cats), astraphobia (lightning), brontophobia (thunder), mysophobia (germs and dirt), nyctophobia (darkness) and ophidiophobia (snakes).

Additions are continually being made to the list so that it clearly reflects our culture and times. In the 16th century phobias centered around demons and Satan. When syphilis was a common concern, during the first half of the 20th century, many people who knew it was spread only by venereal contact nevertheless avoided using public rest rooms and shaking hands for fear of contracting the disease. With advancements in transportation came the fear of flying and riding in elevators and subways. Among today's most common phobias is the fear of the confines of an MRI imaging tube.