There’s a spider on your shoulder. No, your left shoulder. Maybe it slipped down your shirt…

Okay, relax. Almost anyone would react to a spider on their body by gasping, jumping, and brushing off their clothes, then going on through the day without thinking about the spider.

However, some may be so frightened by the idea of a spider crawling on their shoulders that they may choose to stay inside for the day, even if they have to work, or they may continuously think about a spider crawling on them, causing them to have an anxiety-filled day.

The “Mental Health Disorders Sourcebook” defines phobias as an anxiety so serious it interferes with their work, leads them to avoid certain situations or keeps them from enjoying life.

Phobias afflict 12 percent of Americans, and are the most common psychiatric illness in women and the second most common in men over 25 years of age. Agoraphobia causes people to suffer anxiety about being in places or situations from which it might be difficult or embarrassing to escape.

Two common places where agoraphobia is experienced are in an elevator or a room full of people. People suffering from agoraphobia may have panic attacks, and in extreme cases, they may not wish to leave their houses, the sourcebook said.

According to the sourcebook, there are three categories of phobias.

Simple phobias are intense fears of particular objects or situations that are relatively safe. People who suffer from specific phobias know their fear is irrational, but the thought of facing the object or situation brings on panic attacks or severe anxiety.

Specific phobias usually begin in adolescence or adulthood. When children have specific

phobias (for example, fear of dogs or fear of insects), the fears normally disappear over time.

Social phobias can produce fear of being

humiliated or embarrassed in front of other people. This may be related to feelings of inferiority and low self-esteem, and can drive a person to drop out of school, avoid making friends and remain unemployed. Social phobia is often linked to shyness, although it is different than just being shy.

People suffering from social phobia may exhibit the following characteristics: find blushing painfully embarrassing, feel that all eyes are on them, fear speaking in public, fear dating or talking with people in authority, fear using public restrooms and eating out and fear talking on the phone or writing in front of others.

Psychologist Jerry Boyd from Charleston treats patients with phobias. He said agoraphobia is the most common type of phobia he works with.

Boyd also sees patients with specific phobias.

“I treat people who have specific fears, such as the fear of flying or the fear of other specific activities,” Boyd said.

He doesn’t normally see patients who have fears of objects or events they can avoid.

“Agoraphobia is something that can’t be avoided, whereas one afraid of spiders can avoid spiders,” Boyd said.

An article titled “Fears and Dreads” from the World Wide Words Web site includes a little history of phobias and lists common phobias.

Most people only know a very few of the more common words formed using the suffix “-phobia.” Claustrophobia is a fear of enclosed spaces, from the Latin word “claustrum” meaning “a confined or shut-up space,” from which we also derive “cloister,” and “close” in the sense of an enclosure, court or quadrangle.

Acophobia is the fear of heights, which is derived from Greek “akros” for a thing that is topmost, or at the tip or extremity of something. One word physically close to the origin is acropolis, literally “upper city”, but more normally translated “citadel”, as being a structure one usually wishes to place on a commanding height.

Other common phobias are nyctophobia, a fear of the dark, and ochlophobia is the fear of crowds, from the Greek words for night and crowd respectively.

Another well-known phobia is hydrophobia, the fear of water.

People who think they have phobias are recommended to have complete medical and psychiatric evaluations by licensed physicians or psychologists, the “Mental Health Disorders Sourcebook” states. This will allow an accurate diagnosis and reassurance that the symptoms are not being caused by other conditions.

Depending on the severity of the phobia, Boyd said he has a variety of treatments. In severe cases, Boyd refers patients to their family doctors or psychiatrists. He also recommends the medications Paxil and Zoloft to people with serious phobias.

For milder cases, Boyd teaches coping skills to help patients come to grips with their fears. The objective is to desensitize effects phobias have on the patients.

Boyd also recommends reading books on overcoming phobias.

“Two good books I normally recommend are ‘From Panic to Power’ and ‘Hope and Health for Your Nerves,'” Boyd said.

If someone is nervous about a dentist appointment or the first day of school or a new job, the person isn’t suffering from a phobia. Sweaty palms, a pounding heart and feeling shaky are normal reactions to those anxious situations.