I would say that people cannot be "other than themselves". You will just see their other side when they are drunk. And it is quite often the darker, more primitive, violent side, which they suppress under normal conditions, knowing well that other people won't like it.

There is a sentence in some Stephen King's novel (and King is a recovered alcoholic to boot) about the main hero. IIRC it sounds like this:

"There was a dangerous dog in his mind. Sober, he could keep that dog on a leash. Drunk, the leash disappeared."

Maybe you are observing the leash disappearing.