Brain chemistry is at work when someone experiences PTSD. The disorder happens right after someone undergoes a traumatic, critical incident. In essence, the brain has different chemicals, and these chemicals flood the brain while a traumatic event is going on. They are present during the event in order to enable the person to react and survive the trauma. For some people, the brain changes permanently after going through a trauma. In such cases, the individual undergoes what is called a "chemical rewiring." This is the reconstruction that the brain had to make in order to survive the trauma. The newly established rewiring stays that way. This program understands that some war veterans end up living with PTSD. Wow.