What schedule of controlled substances is classified as having the highest potential for abuse?

Schedule I substances are classified as having the highest potential for abuse according to the Controlled Substances Act. This classification indicates that these substances have no accepted medical use in the United States and a high potential for severe psychological or physical dependence. Examples often include drugs like heroin and lysergic acid diethylamide (LSD), which are considered dangerous due to their severe effects and potential for addiction.

In contrast, other schedules have varying potentials for abuse and differing levels of accepted medical use. Schedule II substances also have a high potential for abuse but are recognized as having accepted medical uses with severe restrictions (e.g., opioids like morphine). Schedule III and Schedule IV substances have progressively lower potentials for abuse and are more likely to be used therapeutically in medical practice, with Schedule IV having the lowest potential among those listed. This cumulative understanding of the scheduling system underscores why Schedule I substances are regarded as the most concerning from a public health and regulatory perspective.