Here is a "What if", for you.

You can just email Jacob directly to change your username

Are we talking about every person in the world having dissociative identity with an alter ego that have psychotic/severe antisocial disorder?
Well, in that case the population will decrease cause of mass-murders. There will be no goberments unless dictatorships. The cities will also have less inhabitants cause people will prefer to be alone, for fearing being murdered or hating other people. I imagine the population divided in little villages or houses for an only person in the middle of nothingness. Gangs of murderers will go from one place to another killing people. The weapon manufacture industry will be the most sucessfull of the world. Satanistic cults will be the most influent religions. Everyone will have a pessimistic and black view of life so the Horror and Drama genres will be the favorites in literatura and Kafka and Nietzsche in philosophy. And every romance will be a maniacal love. If one cheats on his/her couple, it will end in murder.
But of course, there will be also people who can control their psychotic side and they will probably build normal countries and cities that the rest of the population will be always attacking.

I'm impressed with this answer. I like the more in depth factor of socialism in comparison.

Few dead people here. A few dead people there. But people would be alot more daring to do things. I think that eventually thought people would be in the middle ground. blaming their personality on things they just really want to do. "Damn I killed that guy at work who was always pissing me off. But it was my other self."

Well then that would depend on your definition of the word "Psychotic"

Most would try and repress it to be honest. Or be just like me and only let it out in places were the repercussions are minimal~

If everyone in the entire world had split personality disorder, there would be more groups dedicated to figuring out how to keep it under control.

I.e. There'd be a lot more pills.

It probably wouldn't be a very fun place to live, dealing with one person like that is enough, can you imagine if everybody was like that?

The Hunger Games IRL

At least it wouldn't be boring. :P

disaster will come and fort

I don't think we would have a functioning society, or if we did it would be something like the Klingons...

I don't think civilization could even be exist or even people could co-exist with each other.

I think it would depend on how often and when we would switch personalities.

You know, uh, the definition of psychotic has nothing to do with violence, nor is it associated with violence. There are literally almost no "psychotic" serial killers on record, compared to the number of obviously non-psychotic killers who are just psychopathic.

Psychotic just means psychosis, so the OP is about a second personality with a break in reality (i.e., hallucinations, delusions), which would probably make everyone hide in their room corners, shrieking as blood ran up the walls and the newscasters on television reported your death while eating the skin off of each other. That's more in line with someone who's psychotic. They'll kill themselves way more often than anyone else. Psychosis doesn't make you homicidal, even if voices are telling you to kill everyone else. If you weren't psychopathic before, those voices would more often drive you to drill a hole in your skull to quiet them.

That's psychosis, dudes. You're probably thinking of psychopathic, but that's not technically violence, either, just an inability to feel certain emotions, like fear or empathy.

Now, if everyone were a psychopath part-time, there would be no society. There would be no organization, anywhere. There would be no authority of any kind, nor any possibility of anything so much as a gang forming. Groups with a shared interest wouldn't even be conceivable to anyone. Psychopaths are incapable of thinking of anything but their own interests, so cooperation would only exist to the extent of how far each individual thinks they can get. It would be complete and total anarchy, and not even the most basic forms of tribalism could exist, since affiliation or cooperation are always going to be impossible for every single person. Currency would be useless and serve no purpose. Even if there were a dictator, no one would listen at all. It wouldn't even have any meaning to anyone else, since there would be no organization that could possibly form any type of government. Everyone would be strictly their own leader, and only to themselves. The entire idea behind antisociality is exactly that: No room for society, just the self. The entire concept of other people having selves is absent.

If both women and men are psychopaths, forget reproduction, or any kind of real relationship at all (every single one would be dubious). Love isn't even a conceivable concept for them, much less raising children. There would be no mothers or fathers in the sense of having a parental role. There's zero chance of any child living past infancy even if they make it that far into development (not likely, since the bearer would have only enemies, and no friends), because there would be no paternal or maternal roles to follow.

Also, Hitler was never psychotic, as an above poster stated. :\

I see mass murder and possible factional global warfare because insanity generally can be catagorized, at least from what I've studied

Nukes would go off, end of the world in a matter of seconds.

Just so u know, you can PM an admin and request a name change/alter.

Yandere and serial killers, that's it。