It's a good premise, backed by solid writing. I read it in one sitting.
I read it in one sitting not because I was loving it. It was suspenseful, yes. Though that feels like the wrong word for this. Suspenseful makes me think of the best mysteries and thrillers. I read this in one sitting out of a need to just have it end, and I frequently wanted it to be over. Likely, this was due to the basic theme hitting too close to home, therefore not a problem with the book itself.
Her reasons, as pointed out by other reviews, are not exactly believable. They are more believable when placed in the context of a teenager's life, where every emotion seems to feel so much stronger than it should, be it good or bad. I bought it enough to get invested, and I found the story as a whole emotionally powerful.
Why three stars, then? Simple. I am not a professional reviewer, I don't review books based on how good they are objectively. I review them based on how much I like them, how they make me feel. For whatever reason, this book made me feel bad. Frustrated, at both the flaws in the book and the fact that not one person saw the signs and helped. I don't know. That's often true in real life, people miss the signs and things happen. I have seen that happen, unfortunately.
Still, I got nothing out of this book. It wasn't a happy book, making me feel good. It wasn't an honestly poignant and emotional book that made me feel something genuine. It was sad. Just sad, but not the right mix of sad and poignant. Just sad. Despair. Angst. Not for me.