What prompted you to fictionalise the story of your grandparents?
I started out trying to write The Storm at the Door as non-fiction and I did all the research I could. I spoke with every person who knew my grandparents well. But I saw that the research had not given me what I wanted - the little details that would animate them in my mind: the way they spoke or the way they were with one another - so I devised this structure out of necessity. The amalgam of memory and imagination is probably familiar to anyone who has a family. You've got a vast set of memories and then all the stuff that's just family myth.
Was the decision to embellish their lives liberating?
It was a moment of liberation and of understanding myself as well - the idea that so much of what I was fascinated by and the ways I had always thought about my grandparents were through fiction. Ultimately, for the art of the book, the fiction was necessary; I don't think it would have been compelling or complete without that.
Did the story of your grandfather's mental illness captivate you from a young age?
Every summer, I inhabit a space that my grandfather inhabited at a house in New Hampshire. At that house the past is still very much alive, in a way that is much less common in America. There's a particularly American compulsion to leave your past and start a memory-less life in new places. I also had a closeness with my mother. She home-schooled me as a kid and was my teacher, my mother and my best friend, so her experiences were intriguing to me. There was this person - my grandfather - who looked like me, who carried himself like I do, whose way of speaking was like mine, who, in fact, had the same diagnosis as I have. This person had existed, and shaped my mother, yet he was totally absent from me.
Given the subject matter, is it difficult for your mother to read the book?
My mother is my first reader. The book bears my name but the project involves her deeply. She was there to guide my understanding. But I am the author, and to animate any character on the page I feel as if, in some way, they have to become an alternate version of myself. In the act of ventriloquism, I felt like I got to know my grandfather - but in another way I think it was more an aspect of myself than him. Then again, you could argue that's how you know anyone.
How did you come to accept that you shared your grandfather's diagnosis of bipolar disorder?
It was a great burden at the time. I think that, ultimately, I'm not bipolar. The psychologist Kay Redfield Jamison - who wrote the brilliant book Touched With Fire - has a thesis I find truth in, which is that the creative process is inherently bipolar. Not all of my close friends agree. I
certainly have bipolar tendencies, but any neurosis is so nebulous. I don't even know if my grandfather had it. It's possible that he struggled, as we all struggle, and his life didn't turn into what he had imagined for it. He was certainly an alcoholic. In today's understanding of things, we would think maybe less of his diagnosis and more of his behaviour.
Are we too quick to diagnose or label mental illness now?
In therapy there's always a self-fulfilling prophecy. I don't believe in multiple personality disorder. I think it was a myth created by therapists and their patients. There's legitimate bipolar disorder, but it's easy to go to a psychologist and believe that you have it, describe the symptoms and be given a diagnosis, because the treatment is not that serious - some lithium, and you're on your way. We are still so far from understanding psychopathology.
You write about yourself only briefly in The Storm at the Door. Why is that?
The story was about my grandparents. I wanted to keep the focus on them, but I also thought a part of that story was their legacy and how I think of them now. It took a long time, and many drafts, to strike the right balance. It's like playing around on a guitar. You don't even know what's a chord and what's not, but eventually your fingers happen to find four strings that sound right together.
“The Storm at the Door" is published by Faber & Faber (£12.99)