Which schedule of controlled substances is categorized as having the highest potential for abuse?

The categorization of controlled substances is based on their potential for abuse, dependence risk, and accepted medical uses. Schedule I substances are classified as having the highest potential for abuse and are deemed to have no accepted medical use in the United States. This means that they are not legally available for prescription and pose significant risks of severe psychological or physical dependence.

Examples of Schedule I substances include heroin, lysergic acid diethylamide (LSD), and methaqualone. Because they are seen as having a high potential for addiction and no recognized therapeutic benefit, they are subject to the most stringent regulations. In contrast, substances in lower schedules, such as Schedule II, Schedule III, and Schedule IV, do have accepted uses in medicine and are regulated differently based on their potential for abuse.