Traits vs. Disorders: multiple personality trait is normal, but most people don’t have it, although many more people have it than have the disorder

Psychological traits do not cause clinically significant distress or dysfunction.

Mental disorders (mental illnesses) do cause clinically significant distress and dysfunction.

Thus, multiple personality trait is normal, as distinguished from multiple personality disorder (aka dissociative identity disorder).

Traits are normal, but not universal. For example, perfect pitch (aka absolute pitch) is normal, but most people don’t have it (1).

Multiple personality trait is common among fiction writers. Ninety percent probably have it. Why? Where do fiction writers come from? Some of the people with multiple personality trait self-select themselves to become fiction writers, because the trait is conducive to the fiction writing process.

But most people don’t have multiple personality trait: probably less than thirty percent of the general public has it (although that is still a lot more than most psychologists realize).

1. Wikipedia. “Absolute Pitch.” https://en.wikipedia.org/wiki/Absolute_pitch