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
University of Sydney
30 participants
Oct 26, 2025
Interventional
Conditions
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
Inclusion Criteria14
- Female patients aged 21+ years
- Meet criteria for AN as per DSM-5 criteria
- BMI equal than 14kg/m2 - 19.5kg/m2
- > 3 years of illness duration
- Current/ past treatments have not maintained remission
- Referral from care team (psychiatrist or GP and clinician)
- Agree to maintain contact with their care team
- Identified support person
- Agree to refrain from psychoactive drugs, nutritional or herbal supplements for at least 24 hours before each dose of psilocybin
- Agree to a washout serotonergic medications if currently prescribed
- Availability for the duration of the study
- Agree to have research team maintain contact with an identified next-of-kin or support person (i.e. close friend) for the duration of the study
- Capacity to consent
- Sufficiently competent in English and mental capacity to provide written informed consent.
Exclusion Criteria24
- History of neurological conditions (e.g. epilepsy)
- Schizophrenia or other psychotic disorders/bipolar disorder
- First or second degree relative with psychotic disorder
- Severe dissociative disorders e.g.
- Diabetes
- Cardiovascular disease
- Uncorrected hypo- or hyperthyroidism
- Abnormal serum electrolytes
- Raised cardiac enzymes
- Abnormal QT interval prolongation at screening or history of this
- Hypertension
- Hepatic or renal failure (e.g., CrCl < 30ml/min)
- Drug or alcohol dependence in last 6 months
- Prior allergy, hypersensitivity or adverse reaction to psychedelic substances
- Emotionally unstable personality, or other psychiatric problem that may jeopardize therapeutic alliance or safety
- Currently an involuntary patient
- Patient being unsafe to manage on an outpatient basis
- History of serious suicide attempts or presence of a suicide/ serious self-harm risk at screening
- History of laxative abuse in the last 3 months
- Unstable physical condition (e.g., weight loss > 2 kg in the prior month)
- Pregnancy (negative pregnancy tests mandatory at screening visits, baseline, and psilocybin dosing sessions) or Nursing
- If sexually active, participants who lack appropriate contraception
- Patients currently or previously (past 3 months) enrolled in another clinical trial of an investigational product
- No email/phone.
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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.
Locations(1)
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ACTRN12623000357651