Anxiety: A feeling of apprehension and fear characterized by physical symptoms such as palpitations, sweating, and feelings of stress. Anxiety disorders are serious medical illnesses that affect approximately 19 million American adults. These disorders fill people's lives with overwhelming anxiety and fear. Unlike the relatively mild, brief anxiety caused by a stressful event such as a business presentation or a first date, anxiety disorders are chronic, relentless, and can grow progressively worse if not treated.

The anxiety disorders include:

• panic disorder,
• obsessive-compulsive disorder,
• post-traumatic stress disorder,
• social phobia (or social anxiety disorder),
• specific phobias, and
• generalized anxiety disorder.

Each of these anxiety disorders has its own distinct features, but they are all bound together by the common theme of excessive, irrational fear and dread.