Find the movie SYBIL. It's real and in most cases they don't know they have it
Yes. Just ask my friend Fred Jenkins.
Yes, multiple personality disorder is very real. I know someone with this disorder, and it's very interesting to observe. The only way to find out if this is something you are afflicted with is by seeing your doctor and psychiatrist.
If you blackout a lot then you probably have it, highly unlikely though. You blackout cuz the other personality takes over.