Multiple Personality begins with surprisingly widespread childhood trauma...

…and since childhood trauma has a wide range of severity, and children differ in their use of dissociative, split personality, defenses, multiple personality has a wide range, from multiple personality trait to multiple personality disorder.

Here is recent news on widespread childhood trauma:

https://www.nytimes.com/2022/03/03/world/asia/new-zealand-child-sexual-abuse.html