Which of the following is classified as a Schedule I drug?

LSD, or lysergic acid diethylamide, is classified as a Schedule I drug due to its high potential for abuse and lack of accepted medical use in the United States. Schedule I substances are considered to have no currently accepted medical treatment in the U.S. and lack accepted safety for use under medical supervision. This classification reflects concerns regarding the drug's potential to cause serious psychological effects and addictive behaviors.

On the other hand, hydrocodone is classified as a Schedule II drug because it has accepted medical uses, though it is still considered highly addictive. Anabolic steroids are classified as Schedule III drugs, as they do have medical applications but can be abused for performance enhancement. Ketamine, while sometimes used illicitly, is classified as a Schedule III drug due to its medical uses in anesthesia and depression treatment.