Highly Illogical Behaviour - John Corey Whaley

Sixteen year old Solomon has agoraphobia. He hasn't left his house in three years, which is fine by him. At home, he is the master of his own kingdom--even if his kingdom doesn't extend outside of the house.

Ambitious Lisa desperately wants to go to a top tier psychiatry program. She'll do anything to get in.

When Lisa finds out about Solomon's solitary existence, she comes up with a plan sure to net her a scholarship: befriend Solomon. Treat his condition. And write a paper on her findings. To earn Solomon's trust, Lisa begins letting him into her life, introducing him to her boyfriend Clark, and telling him her secrets. Soon, Solomon begins to open up and expand his universe. But all three teens have grown uncomfortably close, and when their facades fall down, their friendships threaten to collapse as well.