Post-Traumatic Stress Disorder and DNA Methylation

An epigenetic mechanism, DNA methylation (DNAm) is intrinsically linked to gene expression in response to environmental exposures, such as trauma. There is a growing body of literature indicating the role of DNAm in the disease process of post-traumatic stress disorder (PTSD) and in vulnerability and resilience to PTSD. Epigenetic changes in key hypothalamic-pituitary-adrenal (HPA) axis genes, genes involved in neurotransmission and immune function, and changes in global DNAm have been reported. In this chapter we discuss the mechanisms of DNAm and review the literature of DNAm patterns in HPA axis, neurotransmitter, and immune response genes, as well as in repetitive elements, associated with PTSD. We also discuss early life exposures to stress, how DNAm may mediate sex differences in risk for PTSD, how stress may effect transgenerational epigenetic alterations, and methodological issues to consider when studying DNAm patterns in PTSD. Since DNAm is involved in response and adaption to environmental stimuli, the study of DNAm is highly relevant to PTSD, given the vital role of the environment in the etiology of the disease. Understanding the epigenetic basis of PTSD has considerable public health impact, in that it will advance our knowledge of potential treatment modalities for patients, since epigenetic alterations may be reversible.