Psycho Addiction

 is a form of addiction which can occur in Fallout, Fallout 2, Fallout 3 and Fallout Tactics.

Fallout, Fallout 2, Fallout Tactics
"You feel light-headed."

Using Psycho carries a 20% chance to become addicted. The addiction last for 1 week.

Fallout 3
Using Psycho carries a 10% chance to become addicted.