Post-traumatic stress disorder (PTSD) is a serious psychiatric disorder that may develop in individuals exposed to a traumatic event. The lifetime prevalence of traumatic events serious enough to cause subsequent PTSD shows great variation depending on definition and sample selection, but even the most conservative of estimates would propose that in excess of 300 million patients world-wide meet diagnostic criteria for PTSD. PTSD is a disorder that leads to substantial impairment with huge consequences to both the individual and society. For these reasons, understanding PTSD is of huge significance.
Knowledge of the biological effects of traumatic stress is important to understand why some people develop PTSD following traumatic events and others do not, the symptomatology of PTSD and possible treatment options. The purpose of this paper is to review knowledge of alterations found in the prefrontal cortex, the amygdala, the hippocampus, the hypothalamic-pituitary-adrenal axis and catecholamine levels in PTSD patients.
Results from the reviewed research indicate certain changes in the brain of PTSD patients such as reduced volume and activation of the prefrontal cortex, hyperreactivity of the amygdala in symptomatic states and diminished volumes of the hippocampus. Interpretation of cortisol levels and changes in the hypothalamic-pituitary-adrenal axis is complicated for a number of reasons discussed in this paper, but evidence suggests suppression of cortisol levels in PTSD patients. There is also evidence of increased catecholamine responses to stress in PTSD patients, but this is not convincingly proven to be the case in baseline conditions.