PTSD (Post Traumatic Stress Disorder) is a mental disorder that develops in some people who have experienced a shocking, scary, or dangerous event. Thus being, "trauma". Previously, it was referred to as "Shell Shock". It is natural to feel afraid during and after a traumatic event. Fear triggers many split-second changes in the body to help defend or avoid danger. This “fight-or-flight” response is a typical reaction meant to protect a person from harm. Nearly everyone experiences a range of reactions to trauma; yet, most people recover from initial symptoms naturally. Those who continue to experience symptoms may be diagnosed with PTSD. People who have PTSD continue to feel stress or fear even when they are not in danger.