These episodes are a serious health problem in the U.S. At least 20% of adult Americans, or about 60 million people, will suffer from panic at some point in their lives. About 1.7% of adult Americans, or about 3 million people, will have full-blown panic disorder at some time in their lives, women twice as often as men. The most common age at which people have their first panic attack (onset) is between 15 and 19 years of age. Panic attacks are significantly different from other types of anxiety, in that panic attacks are very sudden and often unexpected, appear to be unprovoked, and are often disabling.

People with generalized anxiety disorder (GAD) display excessive anxiety or worry, most days for at least 6 months, about a number of things such as personal health, work, social interactions, and everyday routine life circumstances. The fear and anxiety can cause significant problems in areas of their life, such as social interactions, school, and work.