What is a Level 1 or 2 controlled substance?

October 10, 2025 •

2 min read

According to the U.S. Drug Enforcement Administration (DEA), controlled substances are classified into five distinct categories or schedules based on their medical use and abuse potential. A Level 1 or 2 controlled substance, officially known as a Schedule I or Schedule II drug, represents the highest level of regulatory control due to its severe risks of abuse and dependence.

Quick Summary

An overview of the stringent classifications for Schedule I and Schedule II controlled substances, detailing their differing levels of medical use, abuse potential, and potential for dependence.

Key Points

Scheduling Basis: Controlled substances are classified into five schedules (levels) based on their potential for abuse and their accepted medical use.
Schedule I (Level 1) Definition: These drugs have a high potential for abuse and no accepted medical use in the US, making them illegal to prescribe.
Schedule II (Level 2) Definition: These drugs have a high potential for abuse but do possess an accepted medical use and can be prescribed with strict regulations.
Legal vs. Medical Use: A Schedule I drug cannot be legally prescribed, whereas a Schedule II drug can be, but without refills.
Dependence Potential: Both Schedule I and Schedule II substances have a high potential for severe psychological and physical dependence.
Examples of Schedules: Common Schedule I drugs include heroin and LSD, while Schedule II includes opioids like fentanyl and stimulants like Adderall.
Legal Consequences: Possession and distribution of both Schedule I and Schedule II drugs can lead to severe felony charges, with penalties often being similar.

Understanding the Controlled Substances Act (CSA)

In the United States, the classification of medications, chemicals, and other substances is governed by the Controlled Substances Act (CSA). This federal law organizes controlled substances into five schedules (or levels), from I to V, based on their acceptable medical use and potential for abuse or dependence. Schedule I represents the highest level of regulation, while Schedule V represents the lowest.

The Criteria for Drug Scheduling

The DEA classifies drugs based on their potential for abuse, accepted medical use, safety profile, and potential for dependence. The primary difference between Schedule I and II is accepted medical use, despite both having high abuse potential.

What is a Level 1 (Schedule I) Controlled Substance?

A Schedule I substance has high abuse potential, no accepted medical use in the U.S., and lacks accepted safety for medical use. Due to having no accepted medical use, they cannot be legally prescribed. Examples include Heroin, LSD, Marijuana, and Ecstasy.

What is a Level 2 (Schedule II) Controlled Substance?

A Schedule II substance has a high potential for abuse but does have accepted medical use in the U.S.. Abuse can lead to severe dependence. These drugs require a prescription and cannot be refilled. Examples include opioids like Hydromorphone and Fentanyl, and stimulants like Adderall and Ritalin. Cocaine is also listed due to limited medical use.

Schedule I vs. Schedule II: A Comparison


Feature	Schedule I (Level 1)	Schedule II (Level 2)
Accepted Medical Use	None.	Yes.
Abuse Potential	High.	High.
Dependence Potential	High.	High.
Prescription Legality	Cannot be prescribed.	Can be prescribed.
Refill Rules	N/A	No refills.
Examples	Heroin, LSD, Marijuana, Ecstasy.	Oxycodone, Fentanyl, Adderall, Cocaine.

The Legal and Medical Ramifications

Drug scheduling impacts how substances are handled, prescribed, and distributed by medical professionals. For law enforcement, it's crucial for legal action. Schedule I drugs are federally illegal. Misuse of Schedule II drugs can also lead to serious felony charges, often similar to Schedule I offenses depending on state law and quantity.

The Evolving Nature of Drug Schedules

Drug classifications can change based on science, medical understanding, and policy. Reclassification requires review by the DEA and FDA.

For more information, visit the {Link: DEA Diversion Control Division website https://www.deadiversion.usdoj.gov/schedules/schedules.html}.

Conclusion

In summary, understanding what is a Level 1 or 2 controlled substance is key to U.S. drug regulation. Schedule I drugs, lacking accepted medical use and having high abuse potential, are illegal to prescribe. Schedule II drugs also have high abuse potential but are medically accepted and available by prescription under strict rules. This system regulates substances for medical use and imposes penalties for illegal activity.

Frequently Asked Questions

The primary difference is the accepted medical use. Schedule I substances have no currently accepted medical use in the U.S., while Schedule II substances have a currently accepted medical use, despite both having a high potential for abuse.

No, a doctor cannot legally prescribe a Schedule I substance because it has no currently accepted medical use in treatment in the United States.

No, prescriptions for Schedule II controlled substances cannot be refilled. A new prescription is required for each refill.

Marijuana remains a Schedule I substance at the federal level, despite state-level legalization for medical or recreational use, because the DEA has not federally reclassified it based on its current criteria.

Illegal possession of either a Schedule I or Schedule II drug can result in serious felony charges under the Controlled Substances Act, with penalties varying based on the quantity and jurisdiction.

While most recreational use of cocaine is illegal, it does have a very limited accepted medical use as a topical anesthetic for certain surgical procedures, which is why it is classified as Schedule II.

While Schedule I and II drugs have a high potential for severe dependence, the potential for dependence decreases for substances in schedules III, IV, and V.