Fallout: New Vegas
It is possible to become addicted to ant nectar, though the 5% chance involved is one of the lowest addiction rates of any consumable in the game. The addiction rate is further reduced by the Chem Resistant, Old World Gourmet ( ), and Big Brained ( ) perks, producing a very small 0.75% chance of addiction; however, the Courier will still become addicted with a 100% chance after frequent use due to the UMON effect, although the effect can be avoided through the use of the Logan's Loophole trait.
Ant nectar addiction used to be incurable due to a bug, but this was fixed in Fallout: New Vegas patch 18.104.22.168x. The console command Player.RemoveSpell 0006dc6e will immediately remove the addiction on the PC version.