Trauma- and stressor-related disorders, such as posttraumatic stress disorder (PTSD), represent the quintessential diathesis-stress paradigm, whereby an extreme environmental stressor interacts with predisposing biological and psychological factors to give rise to impairment. This impairment is characterized by a complex set of symptoms, which in part appear to reflect a dysregulated stress response system. Here, biology serves both as a precipitant of the disorder and as a recipient of the consequences it bears. Although it is not fully understood whether (or which) biological systems or mechanisms are the causes or consequences of trauma- and stress-related disorders, the evidence is clear that individuals with these disorders show biological differences when compared with individuals without these disorders.

The large majority of this work has examined the biological correlates associated ...