Controlled Substances

What is a Controlled Substance?

Controlled substances are drugs that have some potential for abuse or dependence. These drugs are regulated by the federal Controlled Substances Act (CSA) – this law helps the US Government fight against the abuse of these drugs.

The CSA divides controlled substance drugs into five categories called schedules.

Illegal Controlled Substances

Schedule I drugs have a high potential for abuse and currently have no accepted medical use. Examples include heroin, methamphetamine, and lysergic acid diethylamide (LSD).

Controlled Substances that May be Prescribed

Drugs placed in Schedules II - V have an accepted medical use. If approved by FDA, drugs in these schedules could be prescribed to you by your doctor. The schedule number lets you know the potential for abuse and the severity of the effects if a person abuses the drug.

Schedule II drugs have the highest potential for abuse. Abuse of Schedule II drugs may lead to severe psychological or physical dependence. Examples include morphine, oxycodone, and methadone.

Schedule III drugs have less potential for abuse than the drugs or other substances in schedules I and II. Abuse of Schedule III drugs may lead to moderate or low physical dependence or high psychological dependence. Examples include anabolic steroids, codeine and hydrocodone with aspirin or Tylenol®, and certain barbiturates.

Schedule IV drugs have a low potential for abuse relative to the drugs or other substances in Schedule III. Abuse of Schedule IV drugs may lead to limited physical dependence or psychological dependence compared with Schedule III drugs. Examples include Valium® and Xanax®.

Schedule V drugs have a low potential for abuse relative to the drugs or other substances in Schedule IV. Abuse of Schedule V drugs may lead to limited physical dependence or psychological dependence compared with Schedule IV drugs. Cough medicines with codeine are examples of Schedule V drugs.

More information about controlled substances is available on the DEA Web site.