The movie shows how tormenting and tragic PTSD can be and how hard it is to break out of its self-destructive cycle that is often given on to your offspring, especially if you are a single parent. It is very poignant but reflects the reality of people who suffer from this terrible mental illness.
I am absolutely amazed by Shia LeBeouf's acting/transformation in this movie. He has definitely grown as an actor and I have never seen him in such a role before. Mad props!