Here, tumblr, I made this for you.
We say that one gets cancer, or a cold, or kidney disease. One would never think to say that one is cancer. But we say that one is depressed, or bipolar, or schizophrenic. A disease of the body is a condition. But a disease of the mind, we think, is a state of being. We no longer believe, as we did 250 years ago, that the mentally ill are animals, but we are not yet ready to grant that they are fully human either.