PW: In Against Depression, you state that depression is "the most devastating disease known to humankind." That's a pretty bold statement.

Peter Kramer: If you look at the data, diseases like breast cancer and AIDS don't even come close—they're far, far behind depression in terms of the disability they cause, the years lost to illness. I want readers to think about the whole range of harm. Depression is a common disease, and it can begin early in life. People succeed less well at work, their relatives are home from work caring for them, lives are cut short by suicide that is related to depression. There are huge inter-episode effects where people aren't fully back to themselves. The harm to the economy is very, very substantial.

PW: How do you respond when people refer to you as the authority on depression?

PK: It takes some getting used to. With Listening to Prozac [1993], I was looking at a particular issue: What happens when patients who don't have that much wrong with them to begin with—who have a minor level of depression or obsessionality—have an especially marked response to one of the new antidepressants? Why is it such an enormous change if, say, they become a bit more assertive? What kind of temperament do we demand, what kind of happiness do we value? So that was sort of the book I thought I was writing, and I think the book was well received that way, but it also was taken up by the public as if it were a book about depression. I've had more than a decade of being consulted as an expert on depression without necessarily having set out in that direction.

PW: Do you feel stuck talking about it?

PK: As a writer, I wasn't thinking to limit myself to mood disorders or medications. I was trying to use each of the tools of psychiatry to ask—through things that have happened to my patients—what the culture looks like. But there was sort of a Darwinian push by readers and publishers and agents. What got excerpted from Should You Leave? (1997) were the two chapters that concern the overlap of depression and failed relationships. What people want to hear about is depression. Over 10 or so years, I learned a lot about what people do think about depression, and as I followed the literature along, what impressed me was not that the medications had changed, but that our understanding of depression had changed. There was a much crisper, clearer account in psychiatry of what depression is.

PW: More toward a medical model?

PK: Yes. I think the evidence started very clearly to fit the simple medical model. Here was a condition that caused great suffering, it was disorganizing the brain in some regions, it seemed to be causing atrophy or be caused by preceding problems in other parts of the brain. It was affecting the heart, the blood vessels, bones, the components of the blood. If you had a culture that didn't recognize mental suffering as a criterion for illness, you still would—just on the basis of the effects on the heart and blood vessels—say that we needed a public health campaign against depression. I think the fun of the book for me as a writer, the imaginative part of the book, was to ask, "What would it mean for us culturally to be earnest about this notion of depression as disease?"

PW: What do you think is the most common misconception about depression?

PK: That it is only an illness "in a manner of speaking." That it's not disease at the same level as cancer. I think nowadays, in America, if you interview people and ask if depression is a disease, they'd say yes. They'll sign their name to it. But they're saying it metaphorically, that it's something like a disease. In this book I wanted to nudge people across the line. When someone asks is cancer a disease, we don't just say yes, we say "What kind of question is that?" Cancer defines what disease is. I think the same can be true of depression.