Claustrophobia is the fear of being in closed or small space or room and having no escape. It can be triggered by many situations or stimuli, including elevators crowded to capacity, windowless rooms, and even tight-necked clothing. It is typically classified as an anxiety disorder, which often results in panic attacks. The onset of claustrophobia has been attributed to many factors, including a reduction in the size of the amygdala, classical conditioning, or a genetic predisposition to fear small spaces.