The Controlled Substances Act that determines what is and is not a ‘controlled substance’ was made a law by Congress in 1970. It is underneath this law (and connected portions of the law) that the government has the authority to control the manufacture of and distribution throughout the country of any and all pharmaceutical substances. This law put into the effect the classification system that is commonly used today. These classifications are known as the Schedules. There are currently five schedule classes of drugs. In 1970 these schedules were classified and defined with varying degrees of importance. There are two government agencies which decide what classification schedule a drug is to be assigned, the DEA (Drug Enforcement Agency) and the FDA (Food and Drug Administration). There are rare exceptions in which Congress can pass a law into existence that classifies a drug into a schedule category it did not have otherwise. An example of this was when Congress passed a law in 2000 classifying a drug known as GHB (or gamma hydroxy butyrate) as a schedule 1 substance because of its large prevalence on college campuses being used as a ‘date rape’ drug.

The criteria for classification is a lengthy list, but the main points that must be observed before something can be classified are what potential a drug has for abuse by a patient, what if any currently accepted medical uses the drug has, and whether or not the drug is classified by any other country as being a dangerous one (which also includes whether or not the drug is listed in any international treaties the US currently has).