Which of the following is a Schedule I substance?

• A. Heroin
• B. Methadone
• C. Alprazolam (Xanax)
• D. Methamphetamine

Answer: (A)

Understanding substance scheduling helps explain why heroin is the correct choice. Schedule I is reserved for drugs that have no currently accepted medical use in the United States and a high potential for abuse, with no safe, supervised medical use. Heroin fits this: it has no approved medical use and carries a very high risk of dependence and harm, so it sits in Schedule I. The other substances have recognized medical uses, which moves them to other schedules: methadone has legitimate medical uses (pain treatment and opioid-use disorder treatment) and is Schedule II; alprazolam (Xanax) has medical use but sits in Schedule IV due to lower relative abuse potential; methamphetamine does have medical uses in some contexts and is Schedule II.