Is the mental illness of another person just in your head? Thomas Szasz seems to think so, if I read him right.

At the risk of saying "who are you going to believe, my eyes or your data?," I say that this idea is just, well crazy. I've known enough mentally ill people in my day conclude that mental illnesses are real, even if it is possible to stretch the concept beyond all recognition to include, to make something up, the statement that anyone who likes white chocolate must be insane.

Whether or not you believe that a person has a soul, there's no escaping that the brain, an organ of the body, has a large role in determining personality. And if a person can have a diseased heart, why not a diseased brain?

The assertion that all mental illnesses are simply myths or violations of social conventions that we should simply accept as, hey, you say tomato, I say tomato, is one of those claims that makes libertarianism, for all its other virtues unattractive for the vast majority of the population--including those who would otherwise be sympathetic.

As an aside, the question of whether and how to scale back or even end the "war on drugs" is, contrary to the assertions Szasz makes, a separate question from whether mental illness is a biochemical one or a sociological one.