Chems

Chems (a truncation of "chemical") is both a pre- and post-War slang term for "drug". A chem is any chemical, medicine, etc. that is used to cause changes in a person's behavior or biological systems.

Background
Chems were a pre-War term used to describe narcotic drugs and substances that caused numerous temporary side-effects, both positive and negative. Pre-War narcotics include: Mentats, a pre-War "party-drug", originally developed by Med-Tek for medical purposes; Buffout, a "sports-enhancement" drug popularized by athletes; Psycho, a combat-enhancement drug developed per orders of General Chase; and Med-X, a painkiller found in many hospitals. A large drug-trade existed within pre-War society. Skylanes Air Flight 1981 was one of several illegal smuggling operations that utilized jet airliners to smuggle goods across the country.

Little is known about how chems entered the markets of post-nuclear America, though it is commonly accepted by most wastelanders that the Khans invented the chem trade, specializing in the manufacturing of Jet and Psycho. This ability was taught to them by the Followers of the Apocalypse, sometime between 2278 and 2281.

Types of chems
Various chems exist in the wasteland, some more beneficial than others. Each chem has an individual profile, allowing users to "stack" chems to provide a larger bonus than either does individually. Chems may have four or five simultaneous effects, usually with some kind of balance: It might lower one stat while raising another. Abusing chems results in addiction. Addiction to a chem will cause withdrawal symptoms when the chem wears off, resulting in lowered stats unless the user continues to take the drug, or seeks a cure or treatments.

Chems are divided into two groups: addictive, and non-addictive.

Non-addictive chems
Chems can be found lying about individually or inside containers. They can also be purchased from wasteland vendors. While nearly every vendor will have at least a few stimpaks for sale, some chems will need to be purchased from one of the vendors specializing in chems.

Resisting addiction
There are several ways to resist addiction:
 * 1) Don't take chems. It is never necessary to take chems, so prevent addiction by never taking them at all.
 * 2) Select the Chem Resistant perk or trait. This perk confers a 50% resistance to the addictive effect of individual chems. Chems which normally have a 10% addiction rate will be reduced to a 5% rate. If the trait is taken, however, chems will only last half as long.
 * 3) Take a chem antidote. Only the dangerous Jet has an antidote, though. Fixer is also viable (It is intended to be temporary but is currently bugged and provides permanent addiction removal).
 * 4) Fallout: New Vegas has the Logan's Loophole trait which prevents addiction entirely at the cost of limiting the Courier to level 30.
 * 5) Certain perks in Fallout: New Vegas such as Chem Resistant, Brainless and Old World Gourmet reduce addiction chance.

Curing an addiction
Once addicted to a chem, the user has to either continue taking the chem or suffer withdrawal effects specific to the addiction. It is eventually desirable (if not necessary) to cure the addiction. To cure an addiction, the individual has several choices:
 * 1) Wait it out. Quitting cold turkey will eventually purge the addict's system of the chem. However, Jet addiction cannot be shaken this way, nor can tobacco.
 * 2) Seek out a wasteland doctor and pay them a fee to alleviate the addiction.
 * 3) Use My First Laboratory, after purchasing it for either a Megaton home or Tenpenny Tower suite. Likewise, a trip to the Auto-Doc in The Sink will cure addiction.
 * 4) Addictol cures all addictions, but is scarce across the Commonwealth. It can be purchased from traders/doctors occasionally at a high cost.

Behind the scenes
In the release of Fallout 3 in Australia, the game was banned for including references to real drugs. A report was released by the OFLC on why it banned the game. The following is a part of a report that was released:

One of the reasons for the ban was that the controlled drug, morphine, was one of the chems that would have been available in-game. As a result of the ban, Bethesda decided to have it renamed to Med-X. Evidence of this last-minute change is the fact Med-X's editor ID is Morphine and Med-X addiction's editor ID is WithdrawalMorphine.