PTSD has been closely linked to TBI since certain experiences can be traumatic to individuals. PTSD includes re-experiencing symptoms, avoidance, and changes in arousal, cognition, and mood due to severe traumatic events. There is evidence that mTBI is a higher risk factor for PTSD in comparison to severe TBI. In the military community, TBI and PTSD are prominent as the servicemembers experience frequent head injuries since they are constantly deployed. They are also prone to experience psychological trauma. In civilian populations, there has been evidence that supports how people who have mTBI are at higher risk of developing PTSD. Some of the risk factors seen are less education, being black, having a psychiatric history, and having an injury from another traumatic experience. The reasoning behind the workings of TBI is thought to be a reduction of coping capacities due to cognitive impairment, inflammatory responses, and other damage to the brain or psychological trauma.