You are standing in line at your favorite supermarket not doing anything, just groovin' to the Musak. Suddenly you are in the grip of intense fear, even terror. Your heart is hammering, you can hardly breathe, and you don't know if you're going crazy or having a heart attack. You just want to get out of there. What happened? Most likely you just had a panic attack and if you get more of them, you have what is called "panic disorder."

What is panic disorder?

Panic disorder is characterized by sudden and repeated episodes of intense fear or terror accompanied by physical symptoms of at least some of the following

• chest pain
• heart palpitations
• shortness of breath
• shaking
• dizziness
• nausea

Since these symptoms mimic those of a heart attack, people often go through a series of medical tests or procedures and see up to ten doctors before the diagnosis of panic disorder is made.

People with panic disorder develop a high level of anxiety between episodes and begin to fear another attack, avoiding places where an attack has occurred. Ultimately this can lead to agoraphobia, which literally means "fear of the marketplace," and in practice means that they may become housebound. Panic disorder may co-exist with depression and with substance abuse, the latter due to an attempt to self medicate.

What causes panic disorder?

There may be a genetic predisposition causing a biological malfunction. Stressful events like graduating from college, moving to a new city, having a baby, may trigger the onset of panic disorder. The theory is that stressors lower resistance so that the underlying physical predisposition kicks in.