I have a form of arthritis called psoriasis. In my novel U and I, I made much of the fact that I shared this illness with John Updike. I shared it with millions of people, of course, but Updike was the person relevant to me. Psoriasis, as it were, put me in his league, made me a contender. The next step was "Is mine worse?" I had this feeling that the profounder talent would have a truer form of sickness.

I was convinced that because I had a structural form of arthritis, involving all the joints (as compared to simply the skin complaint, which is the surface form) that I must have unplumbed depths of profundity. Mine was not a dilettantish form of the disease and that gave me a triumphant feeling.

I've given up on that idea though. Psoriasis is literally a pain.

I'm really sad that I can't ride a bicycle with my kids. I have to cruise, with one foot on the pedal - the other leg can't bend. It's all a part of the removal of minor privileges. At night in bed I have to sleep with extra pillows under my knees (which is the sort of thing that only one's wife should know).

I've graduated to the grand- master drug Methatrexate. It leaves you with a glum feeling, the same sort of feeling you get after a night of drinking. The drug slows down the illness at the price of destroying my liver.

It's all very odd. I was recently interviewed by a female journalist for a magazine. She began her article with the words: "What everyone knows about Nicholson Baker is that he has psoriasis of the penis." She told the whole world. But that was 10 years ago. It's not true any more, the drugs dealt with that. My lower half is not as happy as it once was, but my skin problem's gone. I couldn't believe she told the whole world.

As for Updike, I still think no one can write like him. And in terms of the illness, there's really no comparison either. Updike had real suffering as a kid - I think he got psoriasis when he was 10 years old - so there's no comparison. I got it when I was a grown-up. It's almost a conversation point...

Nicholson Baker was talking to Charlotte O'Sullivan