During such extreme and terrifying events, time moves slowly, stretching the danger into a long-endured ordeal. The adrenaline response is intense. It may take many days for jitteriness to begin to subside. People may feel unsafe, especially in open areas, and may want to avoid outside spaces. Hypervigilance may continue for a long time.

In an interview two months after the 1991 mass shooting at a Luby’s cafeteria in Killeen, Tex., one survivor stated, “I can’t sit in a restaurant with my back to the wall since then. I have to be facing the door, able to see everything in the room.” Another survivor reported that when someone enters the room, his eyes fixate on the person’s hands, involuntarily scanning for a weapon.

Some people may develop a changed perspective of the world, feeling that it is an unsafe and dark place. Individuals may even view themselves more negatively, perhaps insufficiently heroic.