Psycho (Fallout)

Characteristics
Psycho is unique among Fallout chems in that its main effect - damage resistance - persists in a progressively weaker form as the drug wears off, whereas other drugs have severe "coming down" penalties.

Characters with an odd Agility will get an effective +2 Action Points off using Psycho, comparable to Jet but without the severe addiction risk/penalty.

Psycho cannot raise damage resistance above 90%. Nonetheless, the difference between even 80% and 90% can be the difference between a lethal or harmless critical hit.

Like other chems that reduce a SPECIAL stat in Fallout and Fallout 2, Psycho can be used to exploitatively increase high-level skills for reduced skill points, with simply two doses to lower Intelligence-based skills below a threshold where skill points are more effective, investing in the skills, such that when Psycho wears off, the skill reverts to a higher score than it should have been if having invested the skill points normally.

In Fallout 2, Psycho is rare through most the game, only turning up with increased prevalence in San Francisco. Even then, it is by far the most expensive chem in the game. All this is probably as a consequence of Psycho having an enormously powerful combat effect.

Fallout

 * Vance sells various chems in the Hub's Old Town, including Psycho.
 * Lorri carries two of these.

Fallout 2

 * Frankie has one.
 * Renesco in New Reno sells some.
 * Some can be found in San Francisco.
 * One can be found in a locker on the Enclave Oil Rig.
 * Cal sells a few of these.
 * One of the slavers has this.
 * Flick sells this.
 * Tubby sells this.
 * A Khan raider on Vault 15's first floor carries one.
 * Two are found on the ground in a room in the Sierra Army Depot's fourth floor.
 * Chemmie would have been able to make an unlimited supply of this.

Fallout Tactics

 * Found on a dead body surrounded by dogs in Macomb.
 * Sold by some merchants.
 * Can be stolen from Cypher in the Freeport mission, who carries a single Psycho.