Let's start off by saying trauma affects everyone differently. The definition of trauma can be very broad. What is traumatic to one may not be traumatic to someone else. Some children who have experienced trauma will keep all of their emotions inside, while others may display challenging behaviors. Those who hold their emotions inside are still hurting, but they fly under the wire because their behaviors do not mirror what we think someone with trauma looks like. For children and teens that have experienced trauma, their brains release too much cortisol (the stress hormone) which actually causes damage to the brain. Due to their traumatic history, their brains have not developed properly. If you have a child that has endured trauma and has challenging behaviors, please take into account their history. Difficult behaviors are not always indicative of a child wishing to be defiant.
There is a tremendous amount of research being done on the effects of trauma on the developing brain. Right Turn has compiled a variety of articles and services available on the topic of trauma.