Sarah Cornwell’s debut novel What I Had Before I Had You follows several generations of a family with a history of bipolar disorder.

You’ve worked in other mediums before, including stories and screenwriting. Do you find that this has been a different kind of writing experience?

Yes! For one thing, this novel was with me for 10 years, from inception to publication. I hope never to spend so long hashing out a script or a short story! I wrote some of these sentences when I was much younger, and some more recently. As Olivia grew up and rephrased her attitudes toward her childhood, so did I. I was lucky to study screenwriting as part of my graduate education, since I ended up using dramatic principles to shape Olivia’s story. Screenwriting teaches the value of forward motion, rising tension, and structural simplicity, especially when telling a story that is emotionally and thematically complex.

How did you go about your research?

Concerning early-onset bipolar disorder, I found much of value in The Bipolar Child by Demitri Papolos, M.D., and Janice Papolos. I read many memoirs concerning adult and adolescent experiences of bipolar disorder, and I was grateful for candid conversations with friends with the bipolar diagnosis, as well as with mental health professionals. Before publication, I had a child psychiatrist fact-check the manuscript. I was very careful, though, to write my characters as people, never as collections of symptoms. In fact, I spent years with these characters before I understood that the behaviors I was writing pointed to bipolar disorder at all. Once I made that discovery, I let it color the story, and only then did I begin research to make sure I rendered that illness accurately.

Your novel rests on the border between fantasy and psychological realism. Why this in-between space?

I wrote early drafts of this book in which all magical phenomena were deflated by the end, and others in which the magic was given concrete reality, and none felt right until I found the final balance, I think because this seems most truthful to me. Life seems full of inexplicable connections, glimmers at the edges of our consciousness. We want to believe that the world is a little larger than what we see.

Bipolar disorder is integral to the personalities here, and they are, in many ways, beautiful. In which ways do you think their curse is also a blessing?

The more I wrote teenage Olivia in a hypomanic state, the more jealous I felt of the vividness of her experience and the intensity of her feelings. So many great paintings have been painted, great ideas hatched, and great books written by people in hypomanic states. The rest of us try to reach that headspace through substances, through meditation, through extreme sports, through religion. But in bipolar disorder, the highs come at great cost. As an adult, Olivia has found in motherhood another kind of heightened state—one that is worth the sacrifice of those brightest passions.