Illness of the mind is real illness. It can have severe effects on the body. People who show up at the offices of their doctors complaining about stomach cramps are frequently told, "Why, there's nothing wrong with you except that you're depressed!" Depression, if it is sufficiently severe to cause stomach cramps, is actually a really bad thing to have wrong with you, and it requires treatment. If you show up complaining that your breathing is troubled, no one says to you, "Why, there's nothing wrong with you except that you have emphysema!" To the person who is experiencing them, psychosomatic complaints are as real as the stomach cramps of someone with food poisoning. They exist in the unconscious brain, and often enough the brain is sending inappropriate messages to the stomach, so they exist there as well. The diagnosis — whether something is rotten in your stomach or your appendix or your brain — matters in determining treatment and is not trivial. As organs go, the brain is quite an important one, and its malfunctions should be addressed accordingly.
- from The Noonday Demon by Andrew Solomon