Is it true to have a dissociative personality like what happened on the Narrator played by Edward Norton?

Bro, this movie really freaks me out.

It is realistic to lose control of your body, and even worse, you are unaware of what you have done during the time when you are unconscious and senseless?

When I was young, I tried to develop a different personality to prevent me from getting myself in trouble or tackling tough problems that are inevitable.

Therefore, I do have two sides right now. One is like the narrator, weak, conformist, automatic and dazed(God damn why the narrator doesn't have a name?). The other is like Tyler Durden, strong, rebellious, philosophical and goal-oriented.

But there's a difference. I know exactly both sides are mine. I am integrated--though according to the modern literary theory, this is a flawed perception. I never lose my consciousness except for sleeping. I can't imagine how someone's mind could be taken over by something else. Seriously, the kind of personality, Tyler Durden, violated the will of the narrator in many ways on many occasions. He should've stay not so close to the line and there are no excuses for arrogation. At least, Tyler should do what the narrotor subconsciously agree with. He came too far.

Isn't it a huge threat to human subjectivity, security and the authority of human will?

Moreover, Tyler Durden originates from within the narrator's mind.A fortress can defend itself from external attacks, but when its inner defenses collapse, like the embankments of an anthill, the structure falls apart. I could defend myself from anything outside as long as I am integrated, harmonious and organized. But if I am actually broken, segregated and disordered, what should I count on?(Damn Postmodernism, f* you)

Right now I calm down a little bit. Tyler Durden is like both an instructor and a demon. But after all, he's a active subject. I think the fear of AI is similar to the one of dissociative personality. I still doubt the horrible picture of dissociative personality, though. It's just too panicking.