Epigenetics: What does it explain about trauma survivors?

Most persons who develop PTSD in the aftermath of exposure recover from trauma-related symptoms, but remain at risk for a recrudescence of symptoms. This suggests that there are aspects of the response to high magnitude trauma that are long-lasting, despite variations in symptom intensity over time. Current bio-behavioral models of PTSD fall short of explaining the apparent paradox of an enduring response on the one hand and symptom change over time on the other. However, this phenomenon can potentially be explained by epigenetic mechanisms. Epigenetics (literally: “epi” meaning “in addition to” genetics) refers to a heritable change in the genome that can be induced by environmental events and does not involve an alteration of DNA sequence. Such modifications reflect enduring changes in the function of the DNA that are caused by environmental exposures. These changes can alter gene function influencing its biological activity. This presentation will discuss evidence for such changes in PTSD, and will explain how such mechanisms explain many of the salient features of PTSD, including individual variation in responses to events of similar intensity (e.g., combat exposures), and the relative permanence of biological and psychological alterations associated with the disorder. Current models of stress, or even gene-environment interactions, only partially address the influence of prior exposure(s) on PTSD vulnerability and the long-lasting biological and psychological effects of trauma exposure. In addition, epigenetic modifications can be transmitted intergenerationally, both through the maternal and paternal lines. The implications of such changes as PTSD vulnerability factors will also be discussed.

Conference

English

Rachel Yehuda

Yehuda, R. (2012, October). Epigenetics: What does it explain about trauma survivors? Plenary presented at the 17th EMDR International Association Conference, Arlington, VA