Understanding Drug Schedules & the Controlled Substances Act

Various pills laying on white counter.
David Malan Photographer's Choice

In the United States, the Controlled Substance Act gives the federal government the authority and direction to control the importation, manufacture, distribution, possession and use of certain substances. Together with the Food & Drug Administration, with scientific evidence provided by the Department of Health & Human Services, the Drug Enforcement Administration classifies drugs into schedules based on

  • pharmacological effect and current scientific knowledge
  • potential for abuse,
  • risk to public health, and
  • risk of psychic or physiological dependence

Understanding Drug Classification Schedules

Controlled substances are classified into five different schedules. Schedule I drugs are the most tightly controlled; schedule V drugs are the least tightly controlled of the controlled substances.

Schedule I drugs are those that have a high potential for abuse, no currently accepted medical use in the U.S., and are deemed not acceptably safe for use even under medical supervision. Marijuana, LSD, ecstasy, and heroin are among the most recognizable schedule I drugs.

Schedule II drugs also have a high potential for abuse, and their abuse can lead to severe physical and psychological dependence. However, unlike schedule I drugs, schedule II drugs do have a currently accepted medical use in the U.S. Examples of schedule II drugs include cocaine, morphine, amphetamines, methamphetamine, and PCP.

Schedule III drugs have a potential for abuse, but not as high an abuse potential as schedule I or II drugs. Abuse of a schedule III drug can lead to high psychological dependence, but only moderate or low physical dependence. As with schedule II drugs, schedule III drugs have an accepted medical use.

Schedule III drugs include testosterone preparations like Axiron and AndroGel, ketamine, and anabolic steroids.

Schedule IV drugs have a lower potential for abuse than drugs in schedules I, II, and III. Abuse can lead to only limited physical or psychological dependence. Schedule IV drugs have an accepted medical use. Well known schedule IV drugs include Valium, Xanax, Ambien, Sonata, and phenobarbital.

Schedule V drugs have a low potential for abuse and when abuse occurs, it may only lead to limited physical or psychological dependence. Schedule V drugs have an accepted medical use. Well known schedule V drugs include Lomotil, cough syrups with low-dose codeine, and Lyrica.

States may develop their own schedules for controlled substances. Sometimes a state’s schedule will differ from the federal schedule. For example, marijuana might not be classified as a schedule I drug in your particular state, but it’s still recognized as a schedule I drug by the federal government. In the eyes of the federal government, limits on its manufacture, distribution, possession, and use are still enforced by the Justice Department’s DEA.

This is one of many reasons why health insurance won’t pay for medical marijuana even in states that have legalized it.

In fact, since medical marijuana is a schedule I drug, physicians are at risk of having their DEA registration revoked if they prescribe it, even in states that have legalized its medical use. Instead, physicians in these states recommend medical marijuana rather than prescribe it. Thanks to a ruling by the United States Court of Appeals Ninth Circuit in Conant v. McCaffrey, the federal government can’t revoke a physician’s license to prescribe controlled substances based only on the physician’s recommendation of the use of medical marijuana.


Contant HIV AIDS v. Walters DEA, Caselaw, FindLaw. http://caselaw.findlaw.com/us-9th-circuit/1343211.html. Accessed June 24, 2015.

Regulatory Information, U.S. Food and Drug Administration, Department of Health & Human Services. http://www.fda.gov/regulatoryinformation/legislation/ucm148726.htm#cntlsbb. Accessed June 24, 2015.

Title 21 Unites States Code Controlled Substances Act, Office of Diversion Control, Drug Enforcement Administration, Department of Justice. http://www.deadiversion.usdoj.gov/21cfr/21usc/   Accessed June 24, 2015.

Continue Reading