If he was on anti anxiety meds, he probably should not have been drinking.
The pictures that have been released of Paddock may not be accurate representations of his usual demeanor.
Someone has tried very hard to paint him as a total loser.
I think it highly likely that Paddock was making money by illicit means. That could go a long ways towards explaining his standoffishness.
I Am still not convinced he was the shooter.
That is not an anti-anxiety medicine that one is "on" per se (takes as a matter of routine). Valium are taken as needed and are addictive when taken too often.
Many people take valium and still drink.