I can't remember if there have been rules, but I run them as poisons. 1 Pint of alcoholic beverage is the trigger for a RR. I use the % of alcohol as the RR lvl and I enact an additional -10 RR per extra alcoholic beverage.
Failure by 1-25: some intoxication: frank speech, happy times. 26-50: moderate intoxication: slurred speech, things become unclear. 51-100: Heavy intoxication: Seeing double, movement difficult, Bad decisions. 100+: Bad intoxication: No recollection, very sleepy, no sense of reality.
Addiction factor is just 0.1 (roll every 10 beverages)