Which substance is categorized as a Schedule 1 drug?

The correct choice is heroin, which is classified as a Schedule I drug under the Controlled Substances Act. Schedule I substances are defined as drugs with a high potential for abuse, no currently accepted medical use in treatment in the United States, and a lack of accepted safety for use under medical supervision. Heroin fits this classification due to its high potential for addiction and the severe impact it has on health and societal functioning.

In contrast, marijuana, while still a Schedule I substance at the federal level, has been recognized in many states for its medicinal use, leading to debates about its classification. Codeine and oxycodone, on the other hand, are classified as Schedule II substances because they do have accepted medical uses albeit with a high potential for abuse. Understanding these classifications is crucial for law enforcement personnel, as it informs them about the regulatory framework and the legal implications of different substances.