Agoraphobia is an anxiety disorder characterized by anxiety in situations where the sufferer perceives the environment as being difficult to escape or get help. These situations include, but are not limited to, wide-open spaces, as well as uncontrollable social situations such as may be met in shopping malls, airports, and on bridges. Agoraphobia is defined within the DSM-IV TR as a subset of panic disorder, involving the fear of incurring a panic attack in those environments.