Post-traumatic stress disorder (PTSD) is a serious and common problem affecting some people exposed to a traumatic event. While often associated with the military and emergency responders, PTSD can also affect other people subjected to trauma. For people who have been through a traumatic event, stress may last a long time. Some people may continue to be distressed by the memory of the event. Others may spend time avoiding - or trying to avoid - things that remind them of the event. For some people, their emotions may be numb or negative. Others may be overly stressed or hyper-vigilant.