Psilocybin will remain Schedule I through end of 2027, as no NDA has been filed and DEA rescheduling requires completion of a formal administrative process that FDA approval would trigger but publication volume cannot accelerate.

Psilocybin will almost certainly remain a Schedule I drug (illegal with no accepted medical use) through 2027 because no company has yet filed an NDA (the FDA application required to approve a new drug). Even after an NDA is approved, the DEA (the federal agency that controls drug legality) needs 12-24+ months to formally change psilocybin's legal status. Since the clock hasn't even started, rescheduling by 2028 is unlikely.

The regulatory pathway is structural: FDA NDA approval is a prerequisite for DEA rescheduling review; neither COMPASS nor any competitor has filed an NDA as of May 2026; the administrative law process (notice-and-comment rulemaking or expedited review) takes 12-24+ months even after NDA approval; therefore Schedule I status through end of 2027 is near-certain absent an NDA filing and approval within roughly 6 months, which is implausible.