Jordan King 
White Oaks [EPUB ebook] 

Ten years after Jason Miller killed his best friend in Afghanistan, another drug overdose results in him being sent to White Oaks Mental Hospital to be evaluated as a suicide risk, or so he believes. Soon, Jason realizes the one thing he has in common with the other patients: they are all alone in the world, with no one to follow up on anything being done to them.What, at first, appears to be a chance to finally get clean and start rebuilding his life becomes a desperate struggle to save himself and the other patients from the horrible realities waiting for them behind the walls of White Oaks.