Drug Scheduling: While DEA Decisions Have Aligned with Recent HHS Recommendations, Both Need Comprehensive Policies

GAO reviewed DEA scheduling actions taken from 2020 through 2025 under the Controlled Substances Act (CSA). Of 208 substances for which DEA took scheduling actions during that period, HHS evaluations and recommendations were legally required for 95 substances. DEA considered those evaluations for all 95 required instances. For the 84 substances for which DEA had published a final rule as of December 31, 2025, DEA's scheduling decision aligned with HHS's recommendation in every case. The remaining 11 substances remained under extended temporary scheduling orders as of that date. GAO found that both DEA and FDA maintain policies addressing aspects of the scheduling process, including an existing memorandum of understanding (MOU) governing information sharing between the agencies. However, GAO identified gaps in those policies. DEA lacks policies identifying roles, responsibilities, and procedures specific to scheduling actions. FDA lacks policies or procedures specifying how staff are to conduct scientific and medical evaluations or develop scheduling recommendations. GAO also reviewed an MOU between FDA and NIH's National Institute on Drug Abuse (NIDA), which describes procedures for FDA to consult NIDA when developing scheduling recommendations. That MOU is more than 40 years old and does not reflect current entities or procedures. GAO found that without updating and regularly reviewing the MOU, FDA and NIDA staff may be uncertain about which entities and procedures govern NIDA's contribution to scheduling recommendations. DEA and FDA officials told GAO that scientific disagreements between the two agencies about a substance's appropriate schedule occur but are rare. When they do occur, the agencies discuss their differences, share information, and resolve disagreements before soliciting public comments on a proposed scheduling rule.