Once someone has had a panic attack, for example, while driving, shopping in a crowded store, or riding in an elevator, he or she may develop irrational fears, called phobias about these situations and begin to avoid them. Eventually, the pattern of avoidance and level of anxiety about another attack may reach the point at which the mere idea of doing things that preceded the first panic attack triggers future panic attacks, resulting in the individual with panic disorder being unable to drive or even step out of the house.