A phobia (from the Greek: ?????,Phobos, meaning "fear" or "morbid fear") is defined as a persistent fear of an object or situation in which the sufferer commits to great lengths in avoiding despite the fear, typically disproportional to the actual danger posed, often being recognized as irrational. In the event the phobia cannot be avoided entirely, the sufferer will endure the situation or object with marked distress and significant interference in social or occupational activities.

The three categories are:

  1. Social phobia- fears involving other people or social situations such as performance anxiety or fears of embarrassment by scrutiny of others, such as eating in public. Overcoming social phobia is often very difficult without the help of therapy or support groups. Social phobia may be further subdivided into generalized social phobia (also known as social anxiety disorder or simply social anxiety) and specific social phobia, in which anxiety is triggered only in specific situations.
  2. Specific phobias - fear of a single specific panic trigger such as spiders, snakes, dogs, water, heights, flying, catching a specific illness, etc. Many people have these fears but to a lesser degree than those who suffer from specific phobias. People with the phobias specifically avoid the entity they fear.
  3. Agoraphobia - a generalized fear of leaving home or a small familiar 'safe' area, and of possible panic attacks that might follow. May also be caused by various specific phobias such as fear of open spaces, social embarrassment (social agoraphobia), fear of contamination (fear of germs, possibly complicated by obsessive-compulsive disorder) or PTSD (post traumatic stress disorder) related to a trauma that occurred out of doors.

There is apparently 537 phobias so far but here is a list of Top 10 phobias:

1.Arachnophobia - Fear of Spiders. Half of women and 10 per cent of men have a fear of spiders.

2. Social Phobia - Fear of being evaluated negatively in social situations.In the order of 5.3 million American adults, or about 3.7 percent of people in this age group in a given year, have social phobia.Social phobia typically begins in childhood or teens.

3. Aerophobia - Fear of flying.

4. Agoraphobia - Agoraphobia involves extreme fear and avoidance of any place or situation where escape might be complicated or help unavailable in the event of developing sudden panic-like symptoms.Approximately 3.2 million American, or about 2.2 percent, have agoraphobia.

5.Claustrophobia - Fear of being trapped in small confined spaces.

6. Acrophobia - Fear of heights.

7. Emetophobia - Fear of vomit.

8. Carcinophobia - Fear of cancer.

9. Brontophobia - Fear of thunderstorms.

10.Necrophobia - Fear of death or or dead things

Phobias vary in severity among individuals. Some individuals can simply avoid the subject of their fear and suffer relatively mild anxiety over that fear. Others suffer full-fledged panic attacks with all the associated disabling symptoms. Most individuals understand that they are suffering from an irrational fear, but they are powerless to override their initial panic reaction.