This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Psychiatry
Three years back a woman had exposure to an eahquake and she was successfully saved. After recovery she has nightmares about the episode and she also gets up in the night and feels terrified. The MOST probable diagnosis is : 
Select and explain. 
A. Major depression, B. Post-traumatic stress disorder, C. Mania, D. Schizophrenia
B: Post-traumatic stress disorder
Answer: B: Post-traumatic stress disorder 
Explanation: This woman was exposed to a traumatic event following which she is getting flashbacks about the event and is having difficulty in sleeping. All of these symptoms indicates a diagnosis of post traumatic stress disorder. Post traumatic stress disorder is an anxiety disorder characterized by re experiencing a traumatic event and decreased responsiveness and avoidance of current events associated with the trauma. They experience illusions, sleep problems, nightmares, difficulties in concentration, and hyperaleness. Patients with acute stress disorder develops similar symptoms sholy after the traumatic event but they lasts between 2 and 28 days. Ref: CURRENT Medical Diagnosis & Treatment 2014 chapter 25 By Stua J. Eisendrath, MD.