MDMA-assisted therapy for PTSD (post-traumatic stress disorder) was the closest any psychedelic had come to FDA approval, but in 2024 the FDA sent it back and asked for more evidence. The main problems were that trial participants could easily tell whether they got the real drug or a placebo, which compromises the reliability of the results, and that the data overall wasn't convincing enough. Fixing those issues and running new studies takes years. This matters because approval would have been a historic moment — the first legal psychedelic therapy in the US — and its delay pushes back everything else in the field.
Unresolved confirmatory-data and functional-unblinding concerns from the prior CRL gate any approval. FDA action remains the binding event for downstream scheduling and reimbursement policy. Cleanly falsifiable by an FDA approval letter for an MDMA-PTSD indication in the window.