A new medical condition has emerged in the aftermath of the Vietnam War and the women's movement. To understand PTSD and its impact, one has to first establish a definition for trauma. The first defines trauma as overwhelming life experience, an event or events that overwhelm an individual's psychological or biological coping mechanisms.
Examples are combat, domestic violence or sexual assault.
A newer definition relates to the sudden loss of loved ones. In this definition, trauma is defined as the abrupt cessation of emotional bonds. This could be a result of bereavement, or it could be caused by abrupt removal from an environment where one has formed strong emotional bonds, such as ties to family members. PTSD is a combination of physiological and psychological effects that develop in the aftermath of traumatic events. Hyperarousal is a high level of arousal that occurs when the nervous system has become deregulated.