Study protocol for “psilocybin as a treatment for anorexia nervosa: a pilot study” by Spriggs, MJ, Douglass, HM, Park, RJ, Read, T, Danby, JL, de Magalhães, FJC, Alderton, KL, Williams, TM, Blemings, A, Lafrance, A, Nicholls, DE, Erritzoe, D, Nutt, DJ, Carhart-Harris, RL