I don't think people realize, when they're just getting started on an eating disorder or even when they're in the grip of one, that it is not something that you just "get over." For the vast majority of eating-disordered people, it is something that will haunt you for the rest of your life. You may change your behavior, change your beliefs about yourself and your body, give up that particular way of coping in the world. You may learn, as I have, that you would rather be a human than a human's thin shell. You may get well. But you never forget.

The idea of my future simultaneously thrilled and terrified me, like standing at the lip of a very sheer cliff- I could fly, or fall. I didn't know how to fly, and I didn't want to fall. So I backed away from the cliff and went in search of something that had a clear, solid trajectory for me to follow, like hopscotch.

And so I am feeling numb. It's a curious feeling, and I get it all the time. My attention to the world around me disappears, and something starts to hum inside my head. Far off, voices try to bump up against me, but I repel them. My ears fill up with water and I focus on the humming in my head.

You never come back, not all the way. Always there is an odd distance between you and the people you love and the people you meet, a barrier thin as the glass of a mirror, you never come all the way out of the mirror; you stand, for the rest of your life, with one foot in this world and no one in another, where everything is upside down and backward and sad.

When you're teaching creative nonfiction, it helps to have written about your life in a very open way, because you can say, 'Look, how much are you willing to risk emotionally to write? How careful can you be with the other people you're writing about?

My students know I have a life, they know I've written about my life. They know some detail, probably more than they know about their physics teacher, but I would've told them anyway!

• Eating disorders are addictions. You become addicted to a number of their effects. The two most basic and important: the pure adrenaline that kicks in when you're starving—you're high as a kite, sleepless, full of a frenetic, unstable energy—and the heightened intensity of experience that eating disorders initially induce. At first, everything tastes and smells intense, tactile experience is intense, your own drive and energy themselves are intense and focused. Your sense of power is very, very intense. You are not aware, however, that you are quickly becoming addicted.