A clinical trial of Psilocybin-assisted psychotherapy as a treatment for anorexia nervosa

This interventional Phase 2 trial (n=30), registered on ANZCTR, aims to assess the safety and efficacy of psilocybin-assisted psychotherapy (25mg, 2x) in adults with treatment-resistant anorexia nervosa (AN).

The trial, conducted by the University of Sydney in collaboration with Imperial College London, is funded by the Department of Health, Medical Research Future Fund (MRFF) Innovative Therapies for Mental Illness Grant. The primary intervention involves three oral doses of psilocybin embedded with psilocybin-assisted psychotherapy, consisting of preparatory sessions and supervision during dosing and post-dosing integration sessions. The dosing sessions will be administered by a nurse practitioner and clinical psychologist, with doses of 1 mg in session 1 and 25 mg in sessions 2 and 3, spaced two weeks apart.

The study aims to demonstrate the 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 Eating Disorder Examination and the Eating Disorder Examination-Questionnaire (EDE/EDE-Q) and the Readiness and Motivation Questionnaire (RMQ), respectively. Secondary outcomes include the evaluation of effects on depression, anxiety, obsessions, compulsions, quality of life, cognitive flexibility, inflexible adherence to rigid eating rules, psychological flexibility, mystical experiences, and the therapeutic relationship between patient and clinician.

The trial involves female patients aged 21 to 65 years who meet DSM-5 criteria for AN and have not responded adequately to previous treatments. Exclusion criteria include a history of neurological conditions, schizophrenia, bipolar disorder, severe dissociative disorders, and other specific medical conditions. The recruitment status is not yet recruiting, with an anticipated start date in July 2023.

The principal investigator is Prof Sloane Madden, and contacts for public and scientific queries are Miss Sarah-Catherine Rodan. The study’s ethics application has been approved by the Sydney Local Health District – Concord Repatriation General Hospital. The trial is set to conclude data collection in December 2025, and no individual participant data will be shared, with only de-identified aggregate data disseminated through conference presentations and peer-reviewed publications.

Topic Eating Disorders
Compound Psilocybin
Country Australia
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Trial Details



Trial Number

Sponsors & Collaborators

University of Sydney
The University of Sydney is Australias oldest university. At the psychopharmacology laboratory, researchers have conducted some research with psychedelics.

Imperial College London
The Centre for Psychedelic Research studies the action (in the brain) and clinical use of psychedelics, with a focus on depression.

Data attribution

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