“Multiple Personality Disorder” (MPD) was changed to “Dissociative Identity Disorder” (DID) to emphasize that alternate personalities are parts.

In 1994, the American Psychiatric Association changed the name of Multiple Personality Disorder (MPD) to Dissociative Identity Disorder (DID). The condition itself did not change. The reason for the name change was that the old name had led many people to think that a person with MPD was supposedly more than one person, which had never been implied. The new name was meant to emphasize that there is only one person, who is divided (dissociated) into parts (alternate personalities).

Each alternate personality (alter) originates as a way to cope with, adapt to, or master, a particular problem or situation. Thus, each alter is a specialist with its own self-image, abilities, and world view. This has all the advantages and disadvantages (inconsistency, self-contradiction, limited perspective) of dividedness and specialization. And it also means that the only person, strictly speaking, is all the person’s alters taken collectively.

In this blog, I use the old name, “multiple personality,” for two reasons. First, the new name, “dissociative identity,” has never caught on with the public and is not as widely recognized. Second, the reason that “dissociative identity” has never caught on is that it does not capture what the condition looks like when it is most recognizable: when an alternate personality takes over and acknowledges itself by its own name. (Since this rarely happens—because alters are secret agents, who prefer to remain incognito—most people think the condition is rare.)

I have mentioned the above a number of times in the past, but new visitors to the blog have not read the whole thing, which I strongly recommend.