A generalized feeling of apprehension about possible danger. At the subjective level, the individual may feel a negative mood and worry about possible future danger, which he/she is unable to predict or control.

There is also a physiological component involved in anxiety, including a chronic over-arousal, which readies the person for dealing with the threat or danger if it should occur. The person then attempts to avoid situations where the threat or danger might be encountered.

There are several types of anxiety disorders, including phobias, panic disorder with or without agoraphobia, generalized anxiety disorder, obsessive- compulsive disorder, and posttraumatic stress disorder.