Psilocybin in the treatment of anorexia nervosa: The English transition of a French 1959 case study

Psilocybin is a psychotropic molecule that is a partial agonist of serotonin 2A receptors and is the main psychoactive compound in hallucinogenic mushrooms. After the observation in 1953 in Mexico of ritual practices involving ingestion of such mushrooms, psilocybin was chemically characterized and synthesized in 1958 thanks to the collaboration between the Muséum national d’Histoire naturelle in France and the Sandoz pharmaceutical laboratories in Switzerland. The interest of this substance in psychiatric therapy was then evaluated for the first time at the Sainte-Anne Hospital in Paris, by the team of Professor Jean Delay. Among the patients who received this substance was a 35-year-old woman who was hospitalized for compulsive manifestations emblematic of anorexia nervosa and who experienced an immediate and lasting improvement. The original 1959 article (published in the Annales de la Société Médico-Psychologique) gives details of the patient's family background, biography and clinical examination. It then outlines the observations after two injections of psilocybin four days apart, in particular the autobiographical verbal statements that allowed the patient to understand the psychogenesis of her illness. After a long hiatus, psilocybin is once again the subject of medical research, with clinical trials now underway assessing psilocybin in the treatment of anorexia nervosa (NCT04505189; NCT04052568; NCT04661514) and this 1959 case study, is the first known demonstration of the safety and efficacy of psilocybin treatment of anorexia nervosa. This case study thus provides an interesting insight into possible therapeutic mechanisms and is of great interest to the field moving forward.