• Schedule I Drugs
• Schedule II Drugs
• Schedule III Drugs
• Schedule IV Drugs
• Schedule V Drugs

The Controlled Substances Act (CSA) is part of a larger piece of legislation called the Comprehensive Drug Abuse Prevention and Control Act of 1970. It provides the legal basis for the U.S. government to fight the ongoing war against drugs.

Under the CSA, all drugs are categorized into one of five "schedules." A substance's scheduling is based on three factors: 1) its medicinal value; 2) its possible harmfulness to human health; and 3) its potential for abuse or addiction. Schedule I is reserved for the most dangerous drugs that have no recognized medical use, while Schedule V is the classification used for the least dangerous drugs.

Schedule I Drugs

• have no known medical use in the United States
• have a very high potential for abuse
• are too dangerous to be used even under medical supervision

Drugs classified as Schedule I include 2C-B (Nexus), dimethyltryptamine (DMT), ecstasy (MDMA), GHB, heroin, LSD, mescaline, PMA, and psilocybin.

Schedule II Drugs

• are accepted for medical use in the United States
• may cause severe psychological and/or physical dependence
• have a high potential for abuse

Drugs classified as Schedule II include Adderall, cocaine, hydromorphone, methylphenidates such as Concerta and Ritalin, morphine, and oxycodone.

Schedule III Drugs

• are accepted for medical use in the United States
• may lead to moderate psychological and/or physical dependence
• are less likely to be abused than drugs categorized as Schedule I or Schedule II

Drugs classified as Schedule III include certain barbiturates such as aprobarbital (Alurate), butabarbital (Butisol), and butalbital

(Fiorinal and Fioricet), as well as muscle-building steroids and testosterone.

Schedule IV Drugs

• are accepted for medical use in the United States
• may lead to limited psychological and/or physical dependence
• have a relatively low potential for abuse

Drugs classified as Schedule IV include various benzodiazepines, including alprazolam (Xanax) and diazepam (Valium).

Schedule V Drugs

• are accepted for medical use in the United States
• are less likely to cause psychological and/or physical dependence than drugs in any other Schedule
• have a low potential for abuse

Drugs classified as Schedule V include various over-the-counter medicines that contain codeine.

Source: Compiled by Thomson Gale staff from data reported in "Controlled Substances Act," U.S. Drug Enforcement Administration (DEA), http://www.usdoj.gov/dea/agency/csa.htm (accessed September 4, 2005); and "Controlled Substance Schedules," U.S. Department of Justice, Drug Enforcement Administration (DEA) Office of Diversion Control, http://www.deadiversion.usdoj.gov/schedules/alpha/alphabetical.htm (accessed September 4, 2005).