If you’re confused when you hear the term “drug schedule,” you’re not alone. Even though this phrase isn’t super intuitive, it has significant ramifications for public policy and research. And if you care about psychedelics, it’s essential to understand what the US drug scheduling system means.

Every country controls drugs differently. In the United States, drugs are categorized into five different schedules according to their accepted medical use and the likelihood of abuse. (This system isn’t perfect. More on that below.)

You might have heard terms like “Schedule 1” and “Schedule 2” to describe a range of drugs, including marijuana, cocaine, and MDMA. But what do these schedules mean, and why is it such a big deal? Here’s what you should know.

What Is a Drug Schedule?

A drug schedule is a system of classifying drugs into specific categories. These categories are based on the drug’s potential for abuse and its medical value. For example, schedule 1 drugs have the highest potential for abuse and no accepted medical value, while Schedule 5 drugs have a lower potential for abuse and established medical use.

In 1970, the Controlled Substances Act (CSA) established the US drug scheduling system as we know it today. The CSA regulates the distribution, importation, possession, manufacture, and use of controlled drugs.

Generally, these schedules describe the basic or parent chemical, which means they don’t necessarily describe the drug’s salts, drug isomer, salts of isomers, esters, ethers, and derivatives. However, that doesn’t mean a derivative of DMT is legal. These off-shoots may also be classified as controlled substances. (Confusing, we know.)

According to Section 201 (c), [21 U.S.C. § 811 (c)] of the CSA, the following factors determine which schedule a drug or other substance should be placed: 1

  1. The drug’s potential for abuse (“abuse” refers to the possibility that the substance will be misused)
  2. Any known scientific evidence of its medical use
  3. Current scientific knowledge regarding the substance
  4. The substance’s history and current pattern of abuse
  5. The scope, duration, and significance of abuse
  6. The risk to public health, if any
  7. The substance’s potential for psychic or physiological dependence
  8. Whether it is an immediate precursor of another controlled substance (“precursor” refers to chemicals used to manufacture other drugs)

Why Are Drug Schedules Important?

Drug schedules are important because they regulate controlled substances at the federal level. A drug’s scheduling impacts the following:

  • How easily researchers can access and study a controlled substance
  • The severity of drug crime penalties for the distribution, importation, possession, manufacture, and use of controlled drugs
  • Whether a controlled drug can be prescribed for medical use, as with ketamine
  • How a drug is controlled at the state level
  • Federal tax laws (businesses are prohibited from deducting expenses related to the trafficking of schedule 1 and 2 drugs, which leads to heavy taxes for marijuana businesses) 2

Research has shown that many Schedule 1 drugs, including marijuana, MDMA, and peyote, have therapeutic benefits for conditions ranging from chronic pain to mood disorders. So, why are these substances so heavily regulated, and what would it take for Schedule 1 substances to become prescription drugs?

For federal agencies such as the Drug Enforcement Administration (DEA) and the Food and Drug Administration (FDA), medical value stems from controlled, large-scale clinical trials. Although many studies have emerged that examine the therapeutic applications of psychedelics, we’re still in the early days of psychedelic research. Additionally, the U.S. drug scheduling system creates a classic catch-22: controlled substances require clinical trials to establish their medical use, but researchers have a difficult time accessing controlled substances.

One final note on scheduling: The CSA went into effect during the height of the war on drugs, a global campaign that framed psychoactive drugs as public enemy number one. According to the Drug Policy Alliance, this campaign culminated in “racial discrimination by law enforcement and disproportionate drug war misery suffered by communities of color.” 3

Clearly, this system isn’t perfect. it’s important to keep this context in mind as we discuss different drug schedules because the war on drugs heavily impacted public perception, which continues to impact policy today.

Understanding Each Drug Schedule

Here’s a high-level overview of the different drug schedules and examples of each, per the DEA. 4

Drug Schedule 1 (I)

Also called Schedule I drugs, these substances have no accepted medical use and a high potential for abuse. Examples include:

  • DMT
  • Heroin
  • LSD
  • Marijuana
  • MDMA
  • Peyote

Drug Schedule 2 (II)

Schedule 2 substances (or Schedule II drugs) are considered dangerous and have a high potential for abuse, such as psychological or physical dependence. Unlike Schedule 1 drugs, licensed clinicians can prescribe and administer the drugs in Schedule 2-5. Examples of Schedule 2 drugs include:

  • Adderall
  • Cocaine
  • Fentanyl
  • Methamphetamine
  • Oxycodone
  • Ritalin

Drug Schedule 3 (III)

Schedule 3 substances (aka Schedule III drugs) have a moderate to low potential for physical and psychological dependence. The DEA considers Schedule 3 drugs to have a lower potential for abuse than Schedule 2 drugs but higher than Schedule 4. Examples include:

  • Anabolic steroids
  • Butabarbital
  • Dronabinol (synthetic THC)
  • Ketamine
  • Testosterone
  • Tylenol with codeine

Drug Schedule 4 (IV)

Also written as Schedule IV drugs, Schedule 4 substances have a low potential for abuse and low risk of dependence. Examples of Schedule 4 drugs include:

  • Ativan
  • Ambien
  • Darvocet
  • Soma
  • Tramadol
  • Xanax

Drug Schedule 5 (V)

Schedule V drugs (aka Schedule 5) have a lower potential for abuse. These substances include preparations that contain limited quantities of narcotics. Examples of Schedule 5 drugs include:

  • Lacosamide
  • Lomotil
  • Lyrica
  • Motofen
  • Parepectolin
  • Pyrovalerone

Things to Know

What is a drug schedule?

A drug schedule classifies drugs into specific categories, based is a system of classifying drugs into specific categories. These categories are based on the drug’s medical value and its potential for abuse.

Why are drug schedules important?

  • Drug schedules impact public policy because drugs at higher schedules are subject to more federal regulations and penalties.
  • In order for a drug to have established medical use, federal agencies require large-scale, controlled clinical trials.
  • However, Schedule 1 drugs are more difficult for researchers to access and study. This creates a catch-22 for researchers and psychedelic advocates who want to improve access to psychedelics for mental health therapies.
  • In 1970, the United States Controlled Substances Act (CSA) categorized controlled substances into five different schedules.
  • The CSA went into effect during the war on drugs, which drug policy experts state has contributed to racial discrimination today.
  • Other countries regulate controlled drugs differently.

Understanding each drug schedule

  • Schedule 1 drugs have no accepted medical use and a high potential for abuse.
  • Schedule 2 drugs are considered dangerous drugs that have a high potential for abuse.
  • Schedule 3 drugs have a lower potential for abuse than Schedule 2 drugs. However, they are more considered more dangerous than Schedule 4 drugs.
  • Schedule 4 drugs have a low risk of dependence and a low potential for abuse.
  • Schedule 5 drugs have the lowest potential for abuse of the scheduled substances.
  • Most classical psychedelics are Schedule 1 controlled drugs. Ketamine is an exception as a Schedule 3 drug.

Final Thoughts

In the U.S., the federal drug classification system separates drugs into five separate categories, or “schedules.” The category depends on the drug’s medical use and potential for drug abuse. This system isn’t ideal because it classifies drugs that have therapeutic benefits, like MDMA and psilocybin, as Schedule 1 controlled drugs. As clinical trials establish the medical use for these drugs, we may see conversations about psychedelic drug policy in the future.





1. 21 USC 811: Authority and criteria for classification of substances. Accessed May 3, 2022.

2. The federal government is taxing marijuana businesses to death – Vox. Accessed May 3, 2022.

3. Race and the Drug War | Drug Policy Alliance. Accessed May 4, 2022.

4. Drug Scheduling. Accessed May 4, 2022.