Not brain trauma, Traumatic events.
Post
Traumatic
Stress
Disorder is devastating to adults. When things happen to children the brain doesn't develop naturally afterward. Even less severe stress - such as having to be the caregiver for siblings at a very young age, or being left alone as a developing toddler and many other things have long term repercussions that are physiological as well as emotional.
This book is written in laymans terms (to keep clergy from doing damage rather than helping) and can be found at most bookstores