Are you familiar with Agoraphobia?
I know it is a fear of open spaces
More specifically, Agoraphobia is considered an anxiety disorder. Basically, the person with this sees the environment as unsafe. 
Is it any environment, or specific environments?
Agoraphobia
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
of leaving home or a small familiar 'safe' area, and of possible panic attacks that might follow. It may also be caused by various specific phobias such as fear of open spaces, social embarrassment (social agoraphobia), fear of contamination (fear of germs, possibly complicated by obsessive-compulsive disorder) or PTSD (post traumatic stress disorder) related to a trauma that occurred out of doors.
3. Social phobia, also known as social anxiety disorder, is when the situation is feared as the person