I've started volunteering with an literacy program; I read a book, along with a fifth- or sixth-grade student, then exchange e-mails with him about important themes and ideas. Dear Mr. Henshaw, about a boy who corresponds with one of his favorite authors, was a great way to start the program off -- whether writing for younger readers or telling the story of her life (as she does in Girl from Yamhill, which I read in 2011), Beverly Cleary is a perennial fave.
YA
It's Kind of a Funny Story, Ned Vizzini
A nice bit of YA that takes on mental-health problems in a charming, endearing manner. Perhaps it occludes some of the grittier aspects of depression; perhaps that's fine. This book offers a jumping-off point for discussing issues sans melodrama, etc.