Definition

A drug or other substance that has a high chance of being abused or causing addiction and has no FDA-approved medical use in the United States. Schedule I drugs are tightly regulated by the federal government. Examples of Schedule I drugs are heroin, LSD, and ecstasy. Although marijuana (Cannabis) is classified as a Schedule I drug by the federal government, some states have passed laws that allow the medical and recreational use of marijuana. Also called Schedule I controlled substance.