People with panic disorder have feelings of terror that strike suddenly and repeatedly with no warning. They can't predict when an attack will occur, and many develop intense anxiety between episodes, worrying when and where the next one will strike.

If you are having a panic attack, most likely your heart will pound and you may feel sweaty, weak, faint, or dizzy. Your hands may tingle or feel numb, and you might feel flushed or chilled. You may have nausea, chest pain or smothering sensations, a sense of unreality, or fear of impending doom or loss of control. You may genuinely believe you're having a heart attack or losing your mind, or on the verge of death.

Panic attacks can occur at any time, even during sleep. An attack generally peaks within 10 minutes, but some symptoms may last much longer.

Panic disorder affects about 2.4 million adult Americans and is twice as common in women as in men. It most often begins during late adolescence or early adulthood. Risk of developing panic disorder appears to be inherited. Not everyone who experiences panic attacks will develop panic disorder - for example, many people have one attack but never have another. For those who do have panic disorder, though, it's important to seek treatment. Untreated, the disorder can become very disabling.