A 28-year-old female librarian presents to your primary care clinic. She is visibly distressed. Two weeks ago, while walking home from work, she witnessed a high-speed motor vehicle accident where a pedestrian was struck and killed. She was not physically injured but was interviewed by police at the scene.

Since the event, she has had recurrent, intrusive visual images of the accident. She also has distressing nightmares almost every night. She reports actively avoiding the intersection where the accident occurred, taking a much longer route to work. She feels detached from her husband. She has also lost interest in her usual hobbies, such as reading and gardening. Her husband notes she is “jumpy” and seems on edge all the time. She describes an exaggerated startle response to loud noises and has significant difficulty falling and staying asleep. She also reports feeling as though she is in a daze, with things feeling “unreal.”

Her past medical history is unremarkable. She denies any prior psychiatric history, including anxiety or depression. She drinks one glass of wine on weekends and denies smoking or illicit drug use. She takes no regular medications.