Psilocybin in the treatment of eating disorders: a systematic review of the literature and registered clinical trials

Background: Fluoxetine remains the only pharmacological treatment approved for Bulimia Nervosa, and no other drugs have been approved for eating disorders (EDs). The rationale for exploring psilocybin as a treatment for EDs is compelling, both from biological and psychological perspectives. Moreover, its safety profile in healthy individuals appears favorable. This systematic review aims to examine original research articles and registered clinical trials to assess the current psilocybin’s therapeutic potential in EDs. Methods: Systematic review following the indications of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We searched PubMed, Excerpta Medica Database (EMBASE), and the Cochrane Library from inception until 29 July 2024, with key terms: “psilocybin” and “eating disorders”. Quality was assessed through the Quality Assessment Tool for Before–After (Pre–Post) Studies With No Control Group released by the National Heart, Lung, and Blood Institute (NHLBI). We performed an additional search on the registry of clinical trials available at the website https://clinicaltrials.gov. Results: Two studies met the inclusion criteria for our analysis. The first was an open-label feasibility study involving 10 individuals with Anorexia Nervosa (AN), without a control group. The second was a single case report describing the use of psilocybin in a person with AN. In addition, six registered clinical trials of psilocybin in individuals with EDs were identified. Conclusions: The initial evidence shows that psilocybin might be safe and well-tolerated in AN. The promising results and the need for tests in enlarged samples encourage further research on psilocybin in EDs. Level of evidence VIII: Evidence from nonrandomized controlled clinical trials, nonrandomized clinical trials, cohort studies, case series, case reports, and individual qualitative studies.