Posttraumatic stress disorder (PTSD) may develop following exposure to a traumatic event. According to the 4th edition of the Diagnostic and Statistical Manual of Mental Disorders DSM-IV-TR,1 the essential feature of PTSD is the development of characteristic symptoms following exposure to an extreme traumatic stressor involving direct personal experience of an event that involves actual or threatened death or serious injury, or other threat to one’s physical integrity; or witnessing an event that involves death, injury, or a threat to the physical integrity of another person; or learning about unexpected or violent death, serious harm, or threat of death or injury experienced by a family member or other close associate. The full DSM-IV TR criteria are listed in Table 1.