Trauma
Stress following some kind of trauma, is called Post-Traumatic Stress Disorder( PTSD).It can occur following the experience or witnessing of life-threatening events such as military combat, serious accidents, violent personal assaults like rape, natural disasters or terrorist incidents. People who suffer from PTSD often relive the experience through nightmares and flashbacks, have difficulty sleeping, and feel detached or estranged, and these symptoms can be severe enough and last long enough to significantly impair the person’s daily life. 

Most people who are exposed to a traumatic stressor experience some of the symptoms of PTSD in the days and weeks following exposure. Research suggests that, among individuals who go on to develop PTSD, roughly 30 percent develop a chronic form that persists throughout an individual’s lifetime. The course of chronic PTSD usually has periods of symptom exacerbation and remission or decrease, although for some individuals symptoms may persist at an unremitting, severe level. 

PTSD can be treated by a variety of forms of psychotherapy. Some treatments appear to be quite promising, especially cognitive-behavioral therapy, group therapy, and exposure therapy, in which the patient repeatedly relives the frightening experience under controlled conditions to help him or her work-through the trauma.