1. Drug-Control Laws
The U.S. federal law known as the Controlled Substances Act will serve to illustrate a legal drug-classification system created to prevent and control drug abuse.
This federal law establishes five schedules of classification for controlled dangerous substances on the basis of a drug’s
potential for abuse
potential for physical and psychological dependence
medical value

2. Schedules of Classification
Schedule I drugs have a high potential for abuse and have no currently accepted medical use.
Examples are heroin, marijuana, methaqualone, and LSD.
Criminal penalties (1st time offense for individual trafficking) are 0-20 years/$1 million
(Trafficking = buying/selling drugs illegally)

3. Schedules of Classification
Schedule II drugs have a high potential for abuse and have medical use with severe restrictions.
Examples are cocaine, PCP, and most amphetamine and barbiturate prescriptions.
Criminal penalties (1st time offense for individual trafficking) are 0-20 years/$1 million

4. Schedules of Classification
Schedule III drugs have less potential for abuse and a currently accepted medical use
Examples include all barbiturate prescriptions not covered under Schedule II, such as codeine and anabolic steroids.
Criminal penalties (1st time offense for individual trafficking) are 0-5 years/$250,000

5. Schedules of Classification
Schedule IV drugs have a low potential for abuse and have a current medical use.
Examples include Darvon, phenobarbital, and some tranquilizers such as diazepam (valium) and chlordiazepoxide (librium).
Criminal penalties (1st time offense for individual trafficking) are 0-3 years/$250,000

6. Schedules of Classification
Schedule V drugs must show low abuse potential and have medical use.
Examples include opiate drug mixtures that contain nonnarcotic medicinal ingredients, like 200 mg acetaminophen-codeine preparations
Criminal penalties (1st time offense for individual trafficking) are 0-1 years/$100,000

7. Link for more information
Controlled Substances Schedules (US Department of Justice)