Neurobiological Findings in Post-traumatic Stress Disorder

Abstract

Post-traumatic stress disorder (PTSD) symptoms are present across cultures, with the only differences being the indigenous ways in which affected individuals deal with them. Hence, there must be a common underlying basis for these symptoms. The development of an intense memory for the traumatic experiences encountered, and associated neurobiological alterations, may explain the cross-cultural occurrence of similar PTSD symptoms.This chapter presents selected neurobiological findings in post-traumatic stress disorder (PTSD) in the framework of a neurobiological model of PTSD, the fear network model, which explains the development of strong associative emotional-sensory memories for traumatic events. With repeated exposure to traumatic stressors, this associative network gets strengthened but at the same time detached from the corresponding contextual information. After introducing this theoretical background, we next review current knowledge on genetic risk factors for PTSD development, followed by epigenetic alterations found in trauma survivors with PTSD. This is followed by a section on physiological alterations associated with a diagnosis of PTSD. We elaborate on structural and functional alterations in the brain of trauma survivors with PTSD, which correspond well with the assumptions of the fear network model. Furthermore, we summarize evidence that trauma exposure and subsequent PTSD can have adverse physical health consequences, such as cardiovascular, cerebrovascular, gastrointestinal, musculoskeletal, inflammatory, and autoimmune diseases, and accelerate the aging process, increasing the risk for the earlier onset of age-related diseases. We illustrate on a molecular level which processes increase disease risk in traumatized populations. Finally, we show that at least some PTSD-associated molecular alterations might be reversible through treatment.