Controlled Substances Act of 1970: Definition & History

Instructor: Megan Gilbert

Megan has a master's degree in nursing and is a board certified Women's Health Nurse Practitioner. Her area of clinical focus is the impact of infectious disease on pregnancy. She has experience teaching college allied health classes. She is also a certified EMT and holds a certificate of added qualification in electronic fetal monitoring.

This lesson covers the Controlled Substances Act of 1970. It includes key definitions, the groups of scheduled substances, and a brief history of substance related legislation in the United States.

What is a Controlled Substance?

Imagine that your friend convinced you to sign up for the community soccer league by promising that it would be fun. What she didn't tell you was that you would be sitting in the emergency room with your leg swollen to three times its normal size after the first game.

When you're leaving the hospital with your prescriptions, one looks different than the others. The doctor explains that your pain medication is a controlled substance and the label is printed in a way to make it more difficult to copy.

A controlled substance is a medication (or drug or substance) that is regulated by the government, including its possession, manufacturing, and sale.

The Controlled Substances Act of 1970 (CSA) was a federal act passed by the United States Congress that placed comprehensive drug control policy under federal control. This included the laws related to the manufacturing, possession, sale, import, and distribution of certain substances. The initial bill passed by Congress included a list of substances, but the Drug Enforcement Agency (DEA) and the Food and Drug Administration (FDA) have regulated the ongoing restrictions in partnership.

The CSA also defined five classifications of substances based on their potential addiction, dependence, and their accepted medical uses.

The distinction between dependence and addiction is an important one. Dependence refers to a state of being fully acclimated to a substance where the absence of the substance causes withdrawal, while addiction indicts a compulsion to use a substance that interferes with an individual's ability to function normally.

What determines how a medication is classified?

Schedule I:

  1. Substances with high potential for abuse
  2. Has no currently accepted medical use in treatment in the United States

No prescriptions may be written for Schedule I substances and very limited amounts may be produced - generally, it is only produced and released for research purposes.

Examples: heroin, LSD, MDMA (a.k.a. ecstasy), mescaline (the active ingredient in peyote).

Schedule II

Schedule II substances are those that are:

  1. Substances with high potential for abuse
  2. Have an accepted medical use in the United States
  3. Abuse of the drug may lead to severe psychological or physical dependence

No refills may be provided for these medications. An original prescription is almost always required.

Examples: cocaine, codeine, morphine, hydromorphone, phencyclidine (PCP), pentobarbital

For example, if you were given hydromorphone for your pain from the soccer game, it would belong to this group.

Schedule III

Drugs that belong to schedule III are substances that:

  1. While having potential for abuse, are less likely to be abused than substances in schedule I and schedule II
  2. The drug has an accepted medical use
  3. Has low to moderate risk for physical dependence or high risk for psychological dependence

Schedule III-V medications can have up to 5 refills given, but cannot be filled more than 6 months after they were initially written.

Examples of schedule III substances include ketamine, Marinol, buprenorphine, and anabolic steroids.

Doses of less than 90mg of codeine also fall into this category - for example, you might be treated with a combination of acetaminophen and codeine (known by the trade name Tylenol #3) for your pain.

Schedule IV

Drugs that belong to schedule IV include:

  1. Substances that have a lower potential for abuse than schedule III
  2. Substances that have an accepted medical usage
  3. Substances that lead to only limited physical or psychological dependence compared to schedule III

Examples of schedule IV substances include: alprazolam (Xanax), zolpidem (Ambien), phenobarbital, modafinil (Provigil)

If you were given tramadol for your pain, it would belong to this group.

Schedule V

Drugs that belong to schedule V include:

  1. Substances that have low potential for abuse
  2. Substances that have accepted medical usage
  3. Substances that may lead to only limited physical of psychological dependence compared to schedule IV

Examples of schedule IV substances include: small amounts of codeine (such as in cough syrup), pregabalin (Lyrica), diphenoxylate and atropine (Lomotil)


As you're looking at your forgery-proof prescription label filled with safety features, you may be curious what came before the CSA.

The Food and Drugs Act of 1906 was the first federal law to ban potentially harmful substances - more than 200 laws would follow over the years.

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