Epigenetics in Posttraumatic Stress Disorder

Posttraumatic stress disorder (PTSD) and related stress and anxiety disorders contribute substantially to psychiatric morbidity across the world. PTSD is, by definition, the result of an environmental insult, therefore, there has been long-standing interest in the role of non-genetic factors in the disease. With the dawn of molecular epigenetic approaches to psychiatric disease it has become clear that PTSD and related disorders involve epigenetic factors at multiple levels of analysis, from molecular modifications of DNA and chromatin to behavioral transmission of disease risk across generations in both human patients and animal models of these disorders. PTSD is characterized by abnormal activity in the hypothalamic-pituitary-adrenal (HPA) axis, and epigenetic regulation of this axis clearly plays a role in both susceptibility and outcome in trauma exposure. Early-life adversity also plays a clear role in susceptibility to PTSD, and epigenetic factors clearly play a role in the lasting influence early life has on PTSD and other such disorders. The strength of child abuse and familial environment in the disorder argues strongly for early identification and intervention for the prevention of the disorder. Although our understanding of the epigenetic transmission of these disorders continues to grow, few novel, translational approaches have been developed to target explicitly epigenetic aspects of PTSD or anxiety. Future research should seek to bridge the gap between observation and intervention.