The violence was not that bad for a rated R movie if this had less language and less gore it would be PG-13 but the MPAA does not allow movies with more than 2 F words to be PG-13 I Didn't find it that disturbing. Maybe teens should wait till they are more mature.
Consider talking to your kids before you let them watch this good drama but still it can disturb people. But i would say that older teens will like it. :)
I only watched this for Evan Rachel Wood and she was awesome as was the other actors.The story is a little complex I was a little confused but all in all good film.