This one was actualy quite good. I think the best description of this movie is Requiem for a Dream from the viewpoint of a 10 years old son of a Junkie.
It's a bit weird that this movie is advertised as a Keira Knightley movie. The DVD has a big portrait of her as the coverimage, but she has only a small role(maybe 10 minutes screentime). It was made during the same time as kick it like Backham, which was her big breakthrough.