It gears you up to face a threatening situation. It makes you study harder for that exam, and keeps you on your toes when you're making a speech. In general, it helps you cope. They are illnesses, often related to the biological makeup and life experiences of the individual, and they frequently run in families. There are several types of anxiety disorders, each with its own distinct features.
Anxiety disorders are the most common of all the mental disorders.
NIMH also conducts educational outreach activities about anxiety disorders and other mental illnesses. Detailed information is available throughout the site.