Psychedelics for PTSD: what the evidence shows

MDMA-assisted therapy met its main goal in two Phase 3 trials, in severe PTSD (90 people) and in moderate-to-severe PTSD (104 people). The comparison group got the same therapy with a placebo.¹²

In August 2024 the FDA declined to approve it. Its letter cites unreliable recording of side effects, no proof the benefit lasts beyond 18 weeks and possible selection bias (many participants had used MDMA before), and asks for a new trial.³

In August 2026, MAPS — the non-profit behind the original trials — said the sponsor, Resilient Pharmaceuticals, is resubmitting without a new Phase 3 trial. Resilient itself has not announced it.⁴

Australia allows authorised psychiatrists to prescribe MDMA for PTSD, and Switzerland grants patient-by-patient exceptional licences.⁵⁶

In a 30-person randomised trial, six infusions over two weeks reduced chronic PTSD symptoms more than an active placebo.⁷

A larger trial in 158 military personnel and veterans found no significant PTSD benefit over placebo.⁸

In a US clinic, 117 patients who got at least six infusions with preparation and integration sessions saw their PTSD scores drop by almost half. It's a look back at clinic records with no comparison group.⁹

In 30 US special-operations veterans with traumatic brain injury, magnesium-ibogaine was followed by large drops in PTSD, depression and anxiety a month later. Without a control group, that's a signal, not proof.¹⁰

In an open-label Phase 2 study of 22 people with PTSD, one 25 mg dose was followed by large symptom drops at 12 weeks, with no serious side effects. Without a placebo group, this can't tell us how much was the drug.¹¹

In a randomised crossover trial in 80 veterans, three types of smoked cannabis did no better than placebo on PTSD symptoms.¹²

Reviews rate the wider PTSD evidence as very low quality.¹³