A 65-year-old woman reports being housebound despite feeling physically healthy. Several years ago, she fell while shopping sustaining a severe injury to her back and neck. The event was so upsetting and painful that she experienced flashbacks of the event long after recovery. She eventually regained physical and mental composure and ventured out again. Three months ago, while visiting a friend in the hospital she was mugged while returning to her car. Since the mugging experience she has had recurring nightmares, panic and flashbacks of the fall and the mugging. She rarely ventures outside her home with experiencing near debilitating distress. What is the most likely diagnosis