Genetic Screen for PTSD-Prone Soldiers

Post-traumatic stress disorder (PTSD) develops in a subset of patients exposed to traumatic stress. Twin studies with Vietnam Veterans revealed a role for genetic predisposition in trauma associated anxiety, re-experiencing trauma and avoidance of stimuli related to trauma (True et al., 1993; Goldberg et al., 1990). Genetic factors also influence risk of exposure to trauma suggesting a role for personality traits like neuroticism, impulsivity, and/or preexisting conditions such as anxiety or depression in developing PTSD (Lyons et al., 1993; Stein et al., 2002; Jang et al., 2003). To date, evidence from family and candidate gene association studies has been accumulating for a role of genes related to the hypothalamic-pituary-adrenal axis, the limbic amygdalar frontal pathway mediating fear processing, and the ascending brainstem locus coeruleus noradrenergic system in PTSD (see recent review by (Norrholm and Ressler, 2009)). However, the genetic polymorphisms associated with risk and resilience for PTSD identified so far do not support a strong basis for a genetic main effect in PTSD and do not fully account for the genetic heritability of PTSD found in twin studies. Increasing evidence is accumulating for a strong environmental effect, and indicate that gene x environment interactions (such as e.g., data on social support or childhood abuse) should be included in genetic association studies. These studies therefore require a very carefully phenotyped study population.