Her book Wasted: A Memoir of Anorexia and Bulimia is an autobiographical account of her struggle with eating disorders, written when she was twenty-three.

Her fifth book, published in 2011, Waiting: A Nonbeliever's Higher Power, explores spirituality and what that can mean to someone recovering - from addiction, mental illness, or both - who does not believe in God.

In an interview in August 2015 conducted by Adam Walhberg of Minnpost, Hornbacher revealed the inspiration behind the new book she was working on.

She spoke about "the new edition of DSM-5 (Diagnostic and Statistical Manual of Mental Disorders) [which] was released and it created... an... uproar in psychiatry and brain science.

"[6] In this book, she planned to write profiles of 12 people with mental illness to explore these philosophical issues on a more human level.. We’ve Been Healing All Along was published in 2022.

When Hornbacher was fourteen years old, she was accepted into the prestigious arts boarding school Interlochen in northwest Michigan.

The marriage, and eventual divorce, is also discussed in Madness where she attributes the nuptial failure in part to problems with drugs and alcohol, and largely to her ill-managed bipolar disorder.

Along with her journalism and articles, she teaches in the graduate writing program at Northwestern University in Evanston, Illinois.