Which of the following best characterizes Schedule I substances?

• A. Schedule I substances have accepted medical use
• B. Schedule I substances have moderate potential for abuse
• C. Schedule I substances include methadone and fentanyl
• D. Schedule I substances have high potential for abuse and no accepted medical use; examples heroin and LSD

Answer: (D)

Schedule I drugs are defined as having the highest potential for abuse, with no currently accepted medical use in the United States and no accepted safety for use under medical supervision. This is why they cannot be prescribed or dispensed and are highly restricted. Heroin and LSD are classic examples that illustrate this category. By contrast, substances like methadone and fentanyl have medical uses (though with tight controls) and thus are placed in Schedule II, not Schedule I. The other statements misstate medical usefulness or the level of abuse potential for Schedule I.