This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Neurotic, Stress Related and Somatoform Disorders, Subject name: Psychiatry
Which of the following factors is the most impoant predictor of development of Post-Traumatic Stress Disorder (PTSD) in a 30-year-old man who has just been involved in a road traffic accident? 
Select and explain. 
A. Death of a friend in the accident, B. His age and gender, C. History of panic disorder, D. History of substance abuse
A: Death of a friend in the accident
Answer: A: Death of a friend in the accident 
Explanation: Severity of event or accident is the most impoant predictor for development of PTSD.