Mentats

Mentats are a chem in Fallout, Fallout 2, Fallout 3, Fallout: New Vegas, and Fallout Tactics.

Background
This pre-War chem was created by Med-Tek. They were designed to increase memory related functions and speed up other mental processes. These chalky red pills were a popular party drug, widely appreciated for their effect on creativity.

Mentats were sold in both cardboard and tin packagings, the latter a bit more likely to survive the nuclear holocaust.

They are, of course, highly addictive.

Fallout 3
Mentats return in Fallout 3, though they only increase Intelligence and Perception, omitting the Charisma bonus. As in previous games, using them boosts skills based on those attributes (although not to skill points earned on level up as Mentats do not alter base stats).

Mentats are important at the beginning of Fallout 3; particularly with disarming (or alternatively detonating) the Megaton bomb, as indirectly implied by Lucas Simms. Through the base adjustment to Perception, the Mentats can help raise the player's Explosives skill level above the 25 needed to interact with the bomb.

One of three different kinds of Mentats can be won in a quiz pertaining to the Declaration of Independence at the National Archives, these are:
 * Berry Mentats grant a +5 to Intelligence
 * Orange Mentats grant a +5 to Perception
 * Grape Mentats grant a +5 to Charisma

Given that regular Mentats provide the same type and Strength of bonuses as the Berry and Orange versions (and all in one package) practical-minded players may want to choose Grape Mentats when redeeming their prize vouchers. The unique +5 bonus to Charisma (and consequent +10 to Speech and Barter) may come in handy with difficult speech checks or large bartering sessions.

Fallout: New Vegas
Mentats in the Mojave are different from the ones found in The Capital Wasteland. For one, they grant a Charisma bonus, arguably making them better than alcohol in terms of benefit, although without the Strength benefit, the low addiction rate and the fact that Mentats are much less common than alcohol. They also give significantly smaller bonuses than Capital Mentats. They appear to have the same basic effects as Core Region Mentats.

While the Mentats of New Vegas still give a +2 Intelligence modifier, unlike previous games, the bonus only translates into a +4 bonus to related skills like medicine. Keep this in mind, especially when playing hardcore, as skill checks of 55 and 75 do occur. See the quest, "Beyond the Beef".

It is also possible to craft Party Time Mentats, which confer an augmented +5 bonus to Charisma, in addition to the effects of standard Mentats. However Party Time Mentats also have a drastically decreased effect time of 1 min, a 75% decrease from standard Mentats.

Locations

 * In the base game, Mentats are a little more rare than other drugs, but can be found on most Doctors in the game.
 * In the Big MT, Mentats are extremely common and may be found in large quantities, especially in the Forbidden Dome.

Behind the scenes

 * Their name is a reference to Frank Herbert's Dune, where, in the wake of humanity rejecting artificially intelligent computers and robots, Mentats are humans trained for computer-like mathematical and logical computations. Also of note is that the pills are colored red. Red-stained lips are a distinguishing characteristic of a Dune Mentat.
 * Berry, Orange, and Grape Mentats are also present in the Fallout: New Vegas game files but are not used in-game.