With the current paucity of effective pharmacological and psychological treatments for anorexia, there is a great need for new treatment avenues to be explored. For this study, we will recruit patients who have a primary diagnosis of anorexia nervosa as defined by DSM-V criteria, which has been established by their ED team to have been present for at least 3 years, and who have found other forms of treatment ineffective. Over a period of six weeks, participants who are deemed eligible at screening will partake in eight study visits, including three psilocybin dosing sessions with varying doses. The maximum dose of psilocybin a participant will receive in a single session is 25 mg. Across these eight visits, there will also be two MRI scans, five EEG recordings and a range of psychological measures (questionnaires and interviews). There will be a follow-up period of 12 months following the final study visit.

The inclusion criteria are:

Key Inclusion Criteria:

1. Born female
2. Age 21-65
3. Primary DSM-V diagnosis of Anorexia Nervosa
4. Current diagnosis of Anorexia Nervosa, established by specialist eating disorder care team to have likely been present for >3 years
5. Current or past treatments have not been successful to maintain remission from anorexia
6. Be in the care of a GP and specialist eating disorder team in the UK who can confirm diagnosis and who you agree to have us maintain contact with for the duration of the study
7. Sufficiently competent in English and mental capacity to provide written informed consent
8. BMI ≥14kg/m2 and medically stable
9. Agree to have us maintain contact with an identified next-of-kin for the duration of the study
   

Key Exclusion Criteria:

1. Current or previously diagnosed psychotic disorder
2. Immediate family member with a diagnosed psychotic disorder
3. Unstable physical condition
4. MRI or EEG contraindications
5. A history of laxative abuse in the last three months (more than twice a week for three months)
6. History of serious suicide attempts or presence of a suicide/ serious self-harm risk at screening
7. Currently an inpatient
8. Emotionally unstable personality, history of mania, or other psychiatric problem that the screening clinician feels may jeopardise the therapeutic alliance and/or safe exposure to psilocybin
9. Blood or needle phobia
10. Positive pregnancy test at screening or during the study, or woman who are breastfeeding
11. If sexually active, participants who lack appropriate contraceptive measures
12. Drug or alcohol dependence within the last six months
13. No email access
14. Patients presenting with abnormal QT interval prolongation at screening or with a history of this (QTc at screening above 470ms)
15. Patients who are currently, or have recently (within three months) been enrolled in another CTIMP

This study has reached the maximum number of participants and therefore we have officially closed participant recruitment.  For any questions, please contact the study team on: panorexia.trial@imperial.ac.uk. Please only contact this email address with queries related to the anorexia study. For all other enquiries please email psychedelicresearch@imperial.ac.uk.