Your experiences on the front lines leave scars that may be invisible at first but run deep within you.

PTSD develops as a result of an instinct that intends to protect you from further traumatic experiences. For example, flashbacks force you to relive an experience in detail so you’re better prepared if you face it again. Meanwhile, hyperarousal (being on edge) develops to help you react quickly in another crisis.

While these responses may help you survive, they prevent you from moving on from the traumatic experience.

You need to recognize two physical changes that require treatment and therapy:

• Abnormal levels of stress hormones, like adrenaline, trigger the “fight or flight” reaction. They also help deaden the senses and dull your physical pain. People with PTSD continue to produce high amounts of these hormones even when they are out of danger.

• The hippocampus – the part of the brain that process emotion and memories — appears smaller in scans of people with PTSD. Its cells may not process flashbacks and nightmares properly, so the anxiety remains on a higher level. Treatment of PTSD teaches how to work through those memories so, over time, the flashbacks and nightmares gradually disappear.