Mentats Addiction

Mentats addiction is a form of addiction which can occur in Fallout, Fallout 2, Fallout Tactics, Fallout 3, Fallout: New Vegas, Fallout 4, and Fallout 76.

Fallout, Fallout 2, Fallout Tactics
Mentats have a 15% chance of causing an addiction. It lasts for 1 week. When addicted, it causes a 2 point penalty to Agility and a 3 point penalty to Intelligence.

In Fallout Tactics, the penalty is different and much steeper: a 4 point penalty to Perception, Intelligence and Charisma.

Fallout 3, Fallout: New Vegas
Mentats carry a 5% chance of causing an addiction. When addicted, it causes a 1 point penalty to Intelligence and Perception.

In addition to the Mentats as above in Fallout 3, the Courier can craft Party Time Mentats that in exchange for a Charisma bonus of 5 have an addiction risk of 15%, at otherwise the same effects.

Fallout 4
All variants of Mentats carry a 10% chance of causing an addiction. When addicted, it causes a 1 point penalty to Charisma. The addiction can be cured by visiting a doctor, taking addictol, eating a radscorpion egg omelette or drinking a refreshing beverage.