The in-game text implies that it is possible to get addicted to the various alcoholic and medical substances found in Fallout 3. I'm curious - what are the consequences of addiction and can they be counteracted?
Whiskey has a base 10% chance to give you an addiction which increases each time you consume it.
Upon becoming addicted, withdrawal from Whiskey will give you a penalty of -1 agility and -1 charisma.
In Fallout 3, addictions are permanent until cured by:
Further details about addictions for all the Fallout games can be found on the Fallout Wiki here