The Diagnostic and Statistical Manual of Mental Disorders is often called the "Bible" of psychiatric diagnosis, and the term is apt. The DSM consists of instructions from on high; readers usually disagree in their interpretations of the text; and believing it is an act of faith.

At least the Bible lists only 10 Commandments; the DSM grows by leaps and bounds with every revision. The first edition, published by the American Psychiatric Association in 1952, was a spiral-bound pamphlet that described 11 categories of...