Multiple Personality Trait: What’s in a name? (Isn’t a rose a rose? But in “Romeo and Juliet,” a difference in names was a matter of life and death)

Most people have heard of multiple personality. They think it is rare, but admit that it does, if only rarely, occur. The latest edition of the psychiatric diagnostic manual, DSM-5, estimates its prevalence at 1.5% of the general population (which is quite a few people).

DSM-5’s criteria for making the clinical diagnosis, besides requiring: A. two or more personality states, and B. memory gaps, also requires, C. that it causes the person distress and dysfunction. That third criterion wouldn’t be necessary unless there were people who fulfilled the first two criteria, but were not mental ill.

Unfortunately, there has been no name for having multiple personality, but not being mentally ill. Psychiatry does not have a name for it, because it only has names for mental illnesses.

And because there has been no name for it, psychologists don’t study it and psychology textbooks don’t mention it. And even if psychologists wanted to study it, where would they find it?

Meanwhile, the literary world has long considered fiction writers to be “mad,” in an artistic sort of way; that is, they hear the voices of their characters, and may even say that their characters and imaginary worlds seem, when they are writing, “more real than real” (but they are generally in touch with reality, write bestsellers, and win Nobel prizes).

Indeed, there have long been jokes, and even serious remarks by writers, that writers do have a sort of multiple personality. But “multiple personality” has always meant a mental illness, and they are not mentally ill.

Thus, the term “multiple personality trait” (as opposed to “multiple personality disorder” or “dissociative identity disorder”) is useful.