Abstract

Introduction
Anorexia nervosa (AN) is a life-threatening eating disorder (ED), for which there is a critical need for novel treatment avenues to be explored, such as psilocybin-assisted therapy (PAT) which has shown promising therapeutic effects in other psychiatric conditions. Here, we will present the feasibility and efficacy outcomes resulting from the ongoing Imperial College London “Psilocybin as a Treatment for Anorexia Nervosa” clinical trial. The aims of the study are to assess the feasibility, brain mechanisms and preliminary outcomes of using psilocybin in a psychologically supported setting in this patient group.

Methods
A total of 21 female participants have been recruited (eligibility criteria including: 21-65 years old, primary diagnosis of AN confirmed to have likely been present for >3 years, BMI ≥ 14kg/m2, and have found previous or current treatments ineffective at maintaining remission). Over a six-week period, participants receive three ≤25 mg oral doses of the investigational drug, COMP360 (COMPASS Pathways’ proprietary synthetic psilocybin formulation) in a therapeutic setting. These sessions are separated by two weeks and encompassed by a preparation and integration session. Participants are monitored for adverse events (AEs) throughout their study participation. There is an additional follow-up period of 12-months, comprising questionnaires and interviews. Throughout the study we work with participant support networks, including an identified support person and their specialist ED care team, to aid them in supporting the participant during and after the study. We hypothesise that ED psychopathology, measured using the Eating Disorder Examination interview (EDE) and questionnaire (EDE-Q), and readiness and motivation to recover from AN, measured using the Readiness and Motivation Questionnaire (RMQ), will improve following PAT.

Results
At the time of abstract submission, 18 participants have completed the six-week active period of the study. The final participant will complete the active study period in June 2023. This poster will present the above primary outcome results at the six-week final visit, two weeks after the final psilocybin dose, and at the 3-month follow-up. We will also report the feasibility (e.g., interest, referrals and retention rate) and safety (e.g., AEs) outcomes. Thus far, headaches and nausea have been the most common AEs reported, without the occurrence of any serious AEs.