Which of the following is NOT one of the three categories of drugs?

The term "self-medicated" refers to individuals using substances or remedies to treat their own ailments without professional guidance or a prescription. While self-medication may occur with both over-the-counter (OTC) and prescription (RX) medications, it is not classified as an official category of drugs. The three recognized categories are OTC drugs, which can be purchased without a prescription; RX drugs, which require a prescription from a healthcare provider; and illegal drugs, which are prohibited and have no accepted medical use.

The other categories—OTC, RX, and illegal—are well-defined within the pharmacological system and play key roles in how substances are regulated and used within society. Understanding these categories helps individuals recognize the differences in legality, accessibility, and risks associated with various forms of medication and substances.