Barbara Rice DeShong’s The Mercy is a chilling and ultimately redemptive psychological thriller with deep roots. It follows psychologist Jessica LeFave, loosely based on DeShong herself, who is teetering on the brink of despair due to a suicide in her family. Then Jessica’s best friend, Camilla Cervantes, is found murdered, and a drug cartel is suspected. LeFave turns herself into a sleuth and uncovers a trail of clues leading to the darkest parts of Mexico City. PW talked with DeShong about turning life into fiction and how her work as a psychologist informs her writing.

There are some true-to-life events in the background of this book. Can you talk a bit about them?

Are you asking how and why in the world did I turn my stepdaughter’s suicide into a humorous mystery? The truest answer is that I could not share the experience any other way. When the suicide occurred 25 years ago, there were offers to do “up close and personal” pieces. But I couldn’t talk about what happened for 10 years, much less write anything.

The psychologist in The Mercy—who throws herself into finding a killer instead of off a cliff—shares aspects of my biography, including the suicide. But the real story of the book is about the murder of her emotionally troubled best friend, whose body is found on an altar honoring the angel of death worshiped by a drug cartel.

Why not a memoir? There was no way I could I take this most personal and painful loss and turn it into a product. Fiction allowed me to tell my truth. With fiction, especially a mystery, I could share parts of the world I love—psychology, Mexico, horses, puzzles, friends, and humor.

I didn’t want to talk about bipolar thinking and behavior as a cold list of symptoms. I wanted to lay open the reality. But I also wanted to tell a good story.

How does writing relate to your work as a psychologist?

In psychotherapy we work to deeply observe, to see beneath the surface to find those hidden and denied self-defeating behaviors we’d rather not face—but that are running our lives. In The Mercy, Jessica sets out to know the deepest waters of her best friend and ends up on the dark side of Mexico City faced with her own demons and gasping to breathe herself.

Can you talk a bit about how writing the book helped you, and how writing might help others?

Just as Jessica launches a quest to find a killer without knowing that to succeed she will be required to face her own demons, I began The Mercy without knowing that writing the story would force me into the same dilemma. We psychologists always look for why people do what they do. Jessica believes if she discovers why someone wanted her friend dead, she’ll learn the identity of the murderer, that if she discovers why her stepdaughter killed herself, her world will make sense again. She is wrong.

With The Mercy my goal was to write the sort of book I love—a puzzle only solved by revealing or seeing what goes on in the minds of people struggling with pain, desire, love of all kinds, and desperation; a puzzle that answers questions about unfamiliar worlds.

The writing process helped me achieve leaps in understanding about my own past, as I came to know and grow the troubled woman found murdered at the beginning of The Mercy. I’d recommend creative writing to anyone with knotted memories to unravel. Just keep a tap on the self-criticism, and keep your goal honest. Write because you love to write. If you want to get rich, get a business degree.