The DEA (Drug Enforcement Administration—the federal agency that classifies illegal drugs) has its own separate legal power to review and approve drugs, independent of the FDA (the US drug regulator). If the FDA approves psilocybin for medical use, the DEA will launch its own formal review that typically takes 18+ months to complete. This matters because patients and researchers have to wait even after the FDA says yes.
DEA's independent scheduling authority under the CSA is statutory and not overridden by congressional pressure. Historical precedent (e.g., MDMA scheduling delays) supports DEA exercising independent review. The 18-month minimum extension is grounded in typical DEA scheduling timelines. Confidence slightly reduced from 0.82 because no FDA approval recommendation is currently imminent, making this a conditional prediction with an uncertain trigger event.