“HYPERAROUSAL
After a traumatic experience, the human system of self-preservation seems to go onto permanent alert, as if the danger might return at any moment. Physiological arousal continues unabated. In this state of hyerarousal, which is the first cardinal symptom of post-traumatic stress disorder, the traumatized person startles easily, reacts irritably to small provocations, and sleeps poorly. Kardiner propsed that "the nucleus of the [traumatic] neurosis is physioneurosis."8 He believed that many of the symptoms observed in combat veterans of the First World War-startle reactions, hyperalertness, vigilance for the return of danger, nightmares, and psychosomatic complaints-could be understood as resulting from chronic arousal of the autonomic nervous system. He also interpreted the irritability and explosively aggressive behavior of traumatized men as disorganized fragments of a shattered "fight or flight" response to overwhelming danger.”