I have no way to medically verify this, only personal experience. Several years ago after we were first certified, I took my wife and daughters to Cozumel for a cruise dive. We booked our own boat and had an amazing 2 tank dive with plenty of time for shopping before we had to be back on the ship. My oldest had just turned 21 so they went to Señor Frogs while I hauled the gear back to the boat. I caught up with them and had a margarita and a beer. Over a 2 hour period I had maybe 4 drinks and was surprised that I felt them like I did. We both cut ourselves off when we felt it coming. There was definately a difference. My wife felt the same way. My poor daughter was hammered....but not until we got back to the boat then it hit her like a freight train. None of us had enough to drink for the level of intoxication we felt. Then...just like that it was gone with no hangover or after effects....not even my daughter.
Jay