Jet Addiction

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

Fallout 2
"Everything is moving so slowly... you need to get some more Jet, right NOW!''"

Using Jet carries a 50% chance to become addicted.

Fallout 3, Fallout: New Vegas
Using Jet carries a 20% chance to become addicted.