First of all, the story may be too intense for teens, and the message may fly over their head. The intensity comes from the disturbia the main character faces. This disturbia induces stabbing, free sex (no genitals shown but pretty close), and schizophrenic symptoms (paranoia, hallucinations). The "F" word is commonly used.
If you think the viewer will be overwhelmed by these aspects of the movie, it's advisable not to watch it.
OTHERWISE, it's a very deep story, and the main character undergoes a major psychological transformation in the pursuit of being perfect. I thought it was beautiful, and I rarely leave a movie with the sense of admiration I'm currently feeling.
I would recommend this movie to anyone not offended by sexuality, cursing, or drug use.