Sam has OCD, and it sort of defines her life a bit. She has her friends, who are more of a clique, but a girl leads her to a more artsy group of teens, and she quickly starts to learn about what matters to her and how it can help her with her mental problems.
It's a very straightforward story, and the OCD is front and center in the descriptions, but not so much the story. The plot, instead, is more of a traditional "finding new friends" story with some mental illness aspects to try and help it stand out. What resulted, for me, was a book that I did finish, but really struggled with. It's just almost too straightforward, with the various twists in the plot (especially concerning Caroline, her friend who steers her in the new direction) being telegraphed from miles and miles away.
I think we're seeing a lot of this due to A Fault in Our Stars. Yes, we need more books that look honestly at illness. No, this one really isn't it.