Natalie is a 20-year-old female college student. Her parents are concerned that she seems to have become anxious and withdrawn, so much so that it could delay or prevent her from graduating from college. It has become increasingly difficult for Natalie to leave the house to attend her classes. She has turned down invitations from friends to go out to restaurants, bars, and clubs so often that some of her friends have stopped asking. Once a week she drives around searching for and measuring the distance of safe routes to jog, but she doesn't actually jog anymore (she used to go for runs two or three times a week and ran cross country and track in high school). Driving around with the doors locked is the only time she feels "relatively safe outside of my home," but the weekly drives "don't really do anything to alleviate" her feelings of fear and anxiety.

Her parents note that she started avoiding parks and the wooded areas near the house about a year ago. Natalie reports being easily startled, feeling unsafe or uneasy in everyday situations, and admits to avoiding social situations as much as she possibly can. She also reports having trouble concentrating, "feeling numb," feeling disconnected from people, not being excited about the future, and not enjoying activities and hobbies that she used to enjoy. Her sleep is disturbed, and she reports having a recurring, frightening dream about once a week.

• What are possible diagnoses, and why?
• What additional information would you need to know, if any, in order to feel confident and narrow the diagnosis to one?
  • Differential Diagnosis by the Trees may be helpful to guide this process.
• How would you go about obtaining that information?
• What diagnosis would you make? Include the DSM-5-TR code and list all of the specific symptoms from the diagnostic criteria that you utilized to make the diagnosis.
• What is your treatment plan for Natalie, including specific short-, mid- and long-term goals and specific objectives to help realize each of those overarching goals?