Interesting question, Kate. At some level, many great (and not-so-great) literary works “deal with mental health issues.” Hamlet, anyone? But for books that help, that inspire, that make life a little better…

Slaughterhouse-Five by Kurt Vonnegut is a fictionalized account of the author’s experience as an infantry soldier captured by Germans in the Battle of the Bulge. Held as a POW in Dresden, he survived the horrendous firebombing which destroyed that city. In the book, “Billy Pilgrim has come unstuck in time,” his consciousness flashing backward and forward through the episodes of his life, capturing the experience of disordered memory. The extraterrestrial Tralfamadorians provide the outsider’s point of view, and Billy Pilgrim himself becomes an alien in their world.
All the Sci-Fi aside, this is a touching look at a wounded warrior, struggling with insomnia and relationships but getting through life OK nonetheless. He’s neither a hero nor a failure. Absurd and funny, poignant and generous, the book is a paean to those who died and the living who can’t forget them. So it goes.

Not really a book, just the last, long story in a collection of shorts: The Dead, by James Joyce. Its feast of the Epiphanies nails the comic triumph of aging, the poignancy of young life lost, the lasting impact of the past on the living, the striving to make something of it all, and the unknowable mystery of love. Its last pages may be the finest English prose ever written. It always brings me quietly to tears

Finally, a bit of non-fiction. Victor Frankl’s, Man’s Search for Meaning, is the both a memoir and a deep study of survival. A prominent psychiatrist sent to the concentration camps by Nazis, he not only survives unimaginable horrors, but finds deeper meaning in life and a framework which he uses to help myriad others who struggle with the hardships of life. Inspiring and insightful, this short book transcends all the self-help nonsense with an unflinching look at what really matters.
The choice of material seems a bit grim, but the books themselves have always lifted my spirits and opened my heart.