Mental diseases are not really understood the way, say, liver diseases are understood, as a pathology of the body and its tissues and cells. Researchers understand the underlying structure of very few mental ailments. What psychiatrists call a disease is usually just a label for a group of symptoms. As the eminent psychiatrist Allen Frances writes in his book, “Saving Normal,” a word like schizophrenia is a useful construct, not a disease: “It is a description of a particular set of psychiatric problems, not an explanation of their cause.” - David brooks.