RecruitingPhase 1ACTRN12623000357651

A clinical trial of psilocybin-assisted psychotherapy for treatment-resistant anorexia nervosa

A clinical trial to assess safety and efficacy of psilocybin-assisted psychotherapy for treatment-resistant anorexia nervosa in adults

Sponsor

University of Sydney

Enrollment

30 participants

Start Date

Oct 26, 2025

Study Type

Interventional

Conditions

Anorexia Nervosa

Summary

This study aims to: 1. Demonstrate safety and preliminary efficacy of psilocybin-assisted psychotherapy in reducing core eating disorder psychopathology and increasing motivation to change in AN as assessed by the EDE/EDE-Q and RMQ 2. Evaluate effects of psilocybin on depressive, anxious and obsessional symptoms, cognitive flexibility, quality of life and alliance between therapist and patient.

Eligibility

Sex: FemalesMin Age: 21 YearssMax Age: 65 Yearss

Plain Language Summary

Simplified for easier understanding

Anorexia nervosa is a severe eating disorder characterised by extreme restriction of food intake, intense fear of weight gain, and a distorted body image. It has one of the highest mortality rates of any mental health condition. For people who have had anorexia for many years and have not responded to multiple treatments, options are very limited. Psilocybin — a naturally occurring compound found in certain mushrooms — is attracting significant scientific interest as a potential treatment for conditions that involve rigid, entrenched thinking patterns, and early research in eating disorders is showing promise. This Phase 1 clinical trial will test whether psilocybin-assisted psychotherapy (where participants take psilocybin under close supervision alongside structured psychological support) is safe and shows early signs of benefit in women with long-standing, treatment-resistant anorexia nervosa. The study will carefully measure eating disorder symptoms, motivation to change, depression, anxiety, and quality of life. You may be eligible if you are a woman aged 21 to 65 with a diagnosis of anorexia nervosa, a BMI between 14 and 19.5, and more than 3 years of illness that has not gone into lasting remission despite treatment. A referral from your treating psychiatrist or GP is required, and you must be able to stop certain medications before the psilocybin sessions.

This summary was AI-generated to explain the trial in plain language. It is not medical advice. Always discuss eligibility with your doctor before enrolling in a clinical trial.

Interested in this trial?

Get notified about updates and connect with the research team.

Interventions

The intervention will involve 3 oral doses of psilocybin embedded with psilocybin-assisted psychotherapy (talk therapy). Consisting of at least 1 face-to-face and 1 telehealth preparatory sessions (overall 6-8 hours) prior to first dose, supervision during 3 dosing sessions and 3-post dosing integration sessions. Each participant will receive a total of three psilocybin sessions, each session spaced two weeks apart, the maximum dose will be 25 mg in any session. Dosing sessions will last 6-8 hours. The psilocybin will be administered by the study psychiatrist. The information about the dosage is hidden as the study is single blind. The dosage will become publicly available when the recruitment numbers have been reached and all participants have finished the study up until 12-month follow-up. Eligible participants for the neuroimaging component will also do an EEG and MRI at baseline and 6-weeks end point. Examples of specific content/topics that will be discussed during the dosing sessions will be specific to the participant. During dosing sessions contact is kept to a minimum to encourage participants to explore their own mental state.