Anxiety is an emotion characterized by an unpleasant state of inner turmoil, often accompanied by nervous behavior such as pacing back and forth, somatic complaints, and rumination. It includes subjectively unpleasant feelings of dread over anticipated events.

Anxiety is a feeling of uneasiness and worry, usually generalized and unfocused as an overreaction to a situation that is only subjectively seen as menacing. It is often accompanied by muscular tension, restlessness, fatigue, inability to catch one's breath, tightness in the abdominal region, and problems in concentration. Anxiety is closely related to fear, which is a response to a real or perceived immediate threat; anxiety involves the expectation of future threat including dread. People facing anxiety may withdraw from situations which have provoked anxiety in the past.

Though anxiety may be considered a normal human response, when excessive or persisting beyond developmentally appropriate periods it may be diagnosed as an anxiety disorder. There are multiple forms of anxiety disorder (such as Generalized Anxiety Disorder and Obsessive Compulsive Disorder) with specific clinical definitions. Part of the definition of an anxiety disorder, which distinguishes it from every day anxiety, is that it is persistent, typically lasting 6 months or more, although the criterion for duration is intended as a general guide with allowance for some degree of flexibility and is sometimes of shorter duration in children.

 

Note:   The above text is excerpted from the Wikipedia article Anxiety, which has been released under the GNU Free Documentation License.