Sunnybrook Health Sciences Centre is Canada's largest trauma centre, treating 1,100 patients annually. A traumatic experience can lead to post-traumatic stress disorder, which increases hospital stays, emergency visits and disability. Despite developing leadership to manage a "Code Orange" mass trauma, Sunnybrook lacks guidelines in the psychological management of patients who have experienced trauma. The department of psychiatry currently holds a Traumatic Brain Injury clinic and PTSD services for youth but lacks both immediate intervention, prevention and adult services. This research will enable us to gain best evidence expertise to develop guidelines as well as a sustainable PTSD treatment program, with clear outcomes to assess effectiveness, psychiatric morbidity, use of healthcare, disability and substance abuse.