I got through that first depression with the help of a new psychologist, some anxiety medication, and my soon-to-be ex-wife, who despite everything helped coaxed me back to health. Because depression had never been part of my makeup, my working assumption was that it was a one-off. It was the result, I assumed, of my being traumatized at the thought of divorcing a good person with whom I had raised three children and had shared a life for over 30 years.

But I was wrong. Somehow that episode triggered something, or changed something, in my brain. Three years later, I had a second bout of depression. And then a third a few years after that. And a fourth. In between I would have long stretches of normalcy, as well as shorter stretches of what I now realize was mild mania — hypomania, it’s called — during which I would feel invincible. Deep into middle age, I had become bipolar.

Except that I resisted that diagnosis with every fiber of my being. Partly it was because I was terrified at the idea of having to take lithium, the drug of choice for people with bipolar disorder. (Didn’t it have side effects that caused patients to stop taking it?) But it was also because I was ashamed. Why? I can’t really say. But that feeling was real, and it was powerful.