Party Girl Party Boy

Party Boy or Party Girl (depending on gender) is a perk added to Fallout 3 with the Broken Steel add-on and a main perk in Fallout 4.

Fallout 3
The player will no longer suffer the withdrawal effects from an alcohol addiction.

Bugs
If you pick the rank 2 Party Boy/Girl WHILE you're under the influence of alcohol already, the "stats" menu won't show +2 Strength +2 Charisma etc. Make sure you pick the perk while you're sober to see the effects.