The exact cause of panic disorder is unknown. There is an influence of heredity -- studies suggest that if one identical twin has this disorder, the other will also develop panic disorder 40% of the time. In addition, panic disorder has environmental and learning influences, as it often occurs in family members who are not genetically related to each other, and 60% of identical twins do not share the condition.

Panic disorder occurs twice as often in women as in men. Approximately 2% of the population is affected each year. A person with panic disorder often lives in fear of another attack and may be reluctant to be alone or to be far from medical assistance.

Symptoms usually begin before the age of 25. Although panic disorder can occur in children, it is often not diagnosed until the person is older. People with this condition often undergo medical evaluations for symptoms related to heart attack or other conditions before the diagnosis of panic disorder is made.