Agoraphobia is an anxiety disorder characterized by symptoms of anxiety in situations where the person perceives their environment to be unsafe with no easy way to escape. These situations can include open spaces, public transit, shopping centers, or simply being outside their home. Being in these situations may result in a panic attack. The symptoms occur nearly every time the situation is encountered and last for more than six months. Those affected will go to great lengths to avoid these situations. In severe cases people may become completely unable to leave their homes.