What is happening?

I am searching for any help I can find.  My 17 year old son has been acting differently and it seems I am going to have to figure this out on my own.  He has stopped going to school, is not working, and has little social activity.  His thoughts seem confused and he is unable to speak clearly or communicate effectively.  It started in an obvious manner about 2 months ago in what I have learned was a psychotic break.  He spent 2 weeks in a psychiatric center and hasn't been the same since.  I cannot get a diagnosis and therefore don't know how to help him.  It is breaking my heart and I would appreciate any help anyone has to offer.  Is it schizophrenia?