Posttraumatic stress disorder: A model of the longitudinal course and the role of risk factors

Posttraumatic stress disorder (PTSD) differs from other anxiety disorders i n that experience of a traumatic event is necessary for the onset of the di sorder. The condition runs a longitudinal course, involving a series of tra nsitional states, with progressive modification occurring with time. Notabl y, only a small percentage of people that experience trauma will develop PT SD. Risk factors, such as prior trauma, prior psychiatric history, family p sychiatric history, peritraumatic dissociation, acute stress symptoms, the nature of the biological response, and autonomic hyperarousal, need to be c onsidered when setting up models to predict the course of the condition. Th ese risk factors influence vulnerability to the onset of PTSD and its spont aneous remission. In the majority of cases, PTSD is accompanied by another condition, such as major depression, an anxiety disorder, or substance abus e. This comorbidity can also complicate the course of the disorder and rais es questions about the role of PTSD in other psychiatric conditions. This a rticle reviews what is known about the emergence of PTSD following exposure to a traumatic event using data from clinical studies.