Biology of Posttraumatic Stress Disorder

An understanding of the biological basis of posttraumatic stress disorder (PTSD) requires an examinationof the underlying neurobiology of fear and the factors that might contribute to an unsuccessfultermination of the fear response in some individuals. Several factors may lead to an inadequatetermination of a stress response, and the failure to contain the biological alterations initiated by stressmay have long-term adverse consequences. In particular, a prolonged continuation of biological responsesfollowing stress may lead to an inappropriate pairing of the traumatic memory with distressand may then initiate a cascade of secondary biological alterations. This article examines some of thebiological alterations in PTSD and develops a framework for understanding the development progressionof the neurobiology of this disorder.