Any ideas for a schizophrenia-based plot?

I've been writing a novel and I'm getting quite far along, and I have half of a plot in play. It basically consists of a depressed college guy, who upon almost committing suicide, is persuaded otherwise by a girl with the ability to vanish at will. He becomes infatuated with her, until the end he is admitted into an institution by his family and he comes to terms. He soon discovers the hallucination he fell in love with is a patient there.

It is much deeper than the plot above, and I understand I have a lot of researching to do before writing too much about schizophrenia. I was wondering if any of you out there might have any ideas for more to the story?

I was going to add a figure that's out to get him, but I'm not sure what this figure wants from him, what he is able to do, etc? I need a good idea, I would love you forever!

First of all, schizophrenia shows at a young age, so maybe you should add that his family passed it off as a 'overactive imagination' because they're used to appearing perfect. (Or say his grandma has it, but they hide her away)

The figure that is out to get him could be someone who has sexual OCD with him. She (or he) could be obsesed with sleeping with and/or being impregenated with his children, so when he falls for his 'vanishing' girl, they become violent and very dangerous.

Hope this helps!