Tori, a 23 year-old, is unemployed and afraid to leave her house. She has only left her house once in the past year. Her fear of leaving the house started about a year ago when she was in the supermarket and suddenly experienced a feeling of sheer terror. She felt like she was totally out of control and might die. She had two subsequent attacks, both when she was out of her house, and since then she has been afraid to go out. On the one occasion when she left her house in the past year, she insisted that her best friend accompany her and stay by her side until she returned home. Tori may suffer from .