The essence of multiple personality disorder.
This was indeed an extremely serious topic.
Research on multiple personality disorder in the world was truly scarce, making the term "multiple personality disorder" very, very mysterious.
Not only was multiple personality disorder mysterious and terrifying to ordinary people, but it also seemed quite tricky to specialists.
Because in reality, it was very difficult to discover cases of multiple personality disorder, and even harder to have enough cases for research.
Moreover, even when people conducted research, they still could not find the real cause of multiple personality disorder!
