This was a stressful read for me!
It was a really good story and the subject matter (mental illness) was handled really well. BUT, throughout the book, I was stressed out.
I've worked in the social services field for 18 years, the first 8 of which was exclusively in mental health (including 1 1/2 years in the crisis unit of a state hospital). I had no difficulty imagining the hero's actions/behavior. Then, add on top of that, the obsession of first love/teen love and it was painful to experience the emotions (confusion, loyalty, caring, etc.) of the heroine trying to deal with and understand what the hero was going through.
So, this is definitely not a light-hearted story with a HEA, but it handled a sensitive subject well and was definitely realistic.
I will be reading the second part of these characters' story - which I understand has more of a HEA, but with another emotional ride while getting there - after I read a few light, breezy stories first.