sorry that I am giving you the hardcore side of a personality change. alcohol does not bring that on. it's the person underneath that brings that out. with or without alcohol, eventually that is the person that will emerge.
the longer you are with someone, the more comfortable they feel. they will begin to act like they do when they are drinking. drinking brings out their dark side, they feel less or no inhibitions. when drinking, this is the person that they are.
I can't even answer the thing about near beer. To me it is a gateway to real beer.