Jet Addiction

 is a form of addiction which can occur in Fallout 2, Fallout 3 and Fallout: New Vegas.

Fallout 2
Using Jet carries a 50% chance to become addicted. When addicted to Jet, you suffer from a -1 penalty to Strength and Perception.

Fallout 3, Fallout: New Vegas
Using Jet carries a 20% chance to become addicted. When addicted to Jet, you suffer from a -1 penalty to Agility and Charisma.