"Traumatic events, such as military combat, assault, an accident or a natural disaster, can have long-lasting negative effects. Sometimes our biological responses and instincts, which can be life-saving during a crisis, leave people with ongoing psychological symptoms because they are not integrated into consciousness, known as Posttraumatic Stress Disorder (PTSD). Some of these symptoms include intrusive memories and flashbacks of the event, avoidance, dissociation, or hypervigilance."
- National Alliance on Mental Illness