Crank

Crank is a novel by Ellen Hopkins and is about a girl named Kristina who visits her dad, who she has not seen in 8 years. She meets a boy called Adam, better known as Buddy, and changes into a different person, a monster, called Bree. She starts to understand her father better and better while she's Bree, and decides she is a much better person while she is Kristina. Later, Bree/ Kristina makes a terrible descision and decides to be Bree and Bree only.