You used the chem Nuka-Cola Quantum once too often and now your body is craving for more... and more... and more... well done! You got yourself addicted.
Nuka-Cola Quantum addiction is a form of addiction which can occur in Fallout 3, Fallout: New Vegas and was cut from Fallout 4.
Fallout 3, Fallout: New VegasEdit
A 10% chance to become addicted, resulting in a 1 point penalty to Charisma and 15 point penalty to Radiation Resistance.
In Fallout 4, Nuka-Cola Quantum was intended to cause an addiction. When addicted, the player character would suffer a 15 point penalty to Strength and a 1 point penalty to Charisma.
In Fallout: New Vegas there is only one place to find a Nuka-Cola Quantum, making it difficult to become addicted.