Panic disorder is a diagnosed psychiatric mental condition that causes the sufferer to experience sporadic, intense, and often reoccurring panic attacks.
Panic disorder sufferers usually have a series of intense episodes of extreme anxiety, known as panic attacks. These events may last from several minutes to hours, and may vary in intensity and specific symptoms of panic over the duration (i.e. rapid heartbeat, psychological experience of uncontrollable fear, etc.). Some individuals deal with these events on a regular basis—sometimes daily or weekly. The outward symptoms of a panic attack often cause negative social experiences (i.e. embarrassment, social stigma, ostracization, etc.). As a result, as many as 35% of all individuals with panic disorder also have agoraphobia.
Panic disorder is a serious health problem but can be treated. It is estimated that 1.7 percent of the adult American population alone has panic disorder. It typically strikes in young adulthood; roughly half of all people who have panic disorder develop the condition before age 24, though some sources say that the majority of young people affected for the first time are between the ages of 25 and 30. Women are twice as likely as men to develop panic disorder.
Panic disorder can continue for months or even years, depending on how and when treatment is sought. If left untreated, it may worsen to the point where the person's life is seriously affected by panic attacks and by attempts to avoid or conceal them. In fact, many people have had problems with friends and family or lost jobs while struggling to cope with panic disorder. In some individuals symptoms may occur frequently for a period of months or years, then many years may pass symptom free. In others, the symptoms persist at the same level indefinitely. There is also some evidence that many individuals (especially those who develop symptoms at an early age) may experience a cessation of symptoms naturally later in life (i.e. past age 50)[citation needed]. It is advised however, not to alter any current treatment or medications without the advice of a physician.
For people who seek active treatment early in development, the majority of symptoms can disappear within a few weeks, with no permanent negative effects once treatment is completed.

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http://en.wikipedia.org/wiki/Panic_disorder