PTSD is broken down is the reminder of an earlier event in your life. The memory may cause your body to react the same way it did when you experienced the event. If the reaction is classified as negative and happens frequently, they call it “Post Traumatic Stress Disorder”. It is just the name that is used to define the experience. When we are happy our face reacts by lifting the muscles in our checks – we call that a Smile. PTSD is a physical reaction to a memory.