Definition of Agoraphobia:

Agoraphobia is fear of being in places where help might not be available, and is usually manifested by fear of crowds, bridges, or of being outside alone.

Causes, incidence, and risk factors:

Agoraphobia often accompanies another anxiety disorder, such as panic disorder or a specific phobia.

If it occurs with panic disorder, the onset is usually in the 20s, and women are affected more often than men. People with this disorder may become housebound for years, which is likely to hurt social and interpersonal relationships.