Single‑Dose Psychedelics Alter Human Brain Anatomy

A small Nature Communications study using diffusion MRI reports that one 25 mg dose of psilocybin produced measurable changes in white‑matter diffusion metrics, with some tracts showing increased density one month later, and those who had larger acute entropy spikes reported bigger wellbeing and insight gains. The result is preliminary (small sample, indirect DTI measures) but suggests a biological route—structural plasticity—by which a single psychedelic session could yield lasting psychological change. — If replicated, it reframes psychedelic use from ephemeral subjective effects to potentially durable neuroanatomical interventions, affecting clinical practice, regulation, and public expectations about 'one‑and‑done' psychedelic therapies.