Not necessarily. I'm thinking of TV shows now (yes I need to go out more) where people lose their inhibitions (House did it iirc), and they "became" assholes - or they were assholes all along.

But if you're an asshole on the inside but it never comes out, are you really one? This is a pretty dangerous trap. Compare abusive situations where someone needles someone else for ages until they've had enough and the target gets angry. What would be a good response? "I'm sorry I made you angry" or "I knew you were really like this all along!"

(there is no correct answer by the way, it depends on many factors and relationships can't be abstracted away that easily, let alone by an external person on the internet who hears only one side of the story)

Anyway, if Hitler was Hitler but had filters so he never actually said what was really on his mind, we wouldn't have had WW2 and co. In theory.