Psilocybin as a Treatment for Anorexia Nervosa: A Pilot Study

Anorexia nervosa is the most fatal of all psychiatric conditions. With the current paucity of effective pharmacological and psychological treatments, and fewer than half of those diagnosed making a full recovery, 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 specialist ED team to have been present for at least 3 years, and who have found other forms of treatment ineffective. Over a period of 6 weeks, participants who are deemed eligible at screening will partake in 8 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 8 visits, there will also be 2 MRI scans, up to 5 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.

Inclusion criteria

• Primary DSM-V diagnosis of Anorexia Nervosa
• Current diagnosis of Anorexia Nervosa, established by specialist eating disorder care team to have likely been present for >3 years
• Current or past treatments have not been successful to maintain remission from anorexia
• Be in the care of a GP and specialist eating disorder team in the UK
• Have a GP and specialist eating disorder team in the UK who can confirm diagnosis
• Sufficiently competent in English and mental capacity to provide written informed consent
• BMI ≥14kg/m2 and medically stable
• Capacity to consent
• Agree to have us maintain contact with an identified next-of-kin for the duration of the study
• Agree to have us maintain contact with GP and/or specialist eating disorder team as required, for the duration of the study

Exclusion criteria

• Current or previously diagnosed psychotic disorder
• Immediate family member with a diagnosed psychotic disorder
• Unstable physical condition e.g., rapid weight loss > 2kg in the prior month
• Abnormal serum electrolytes, raised cardiac enzymes, hepatic or renal dysfunction
• MRI or EEG contraindications
• A history of laxative abuse in the last 3 months (more than twice a week for 3 months)
• History of serious suicide attempts or presence of a suicide/ serious self-harm risk at screening
• Currently an involuntary patient
• 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
• Blood or needle phobia
• Positive pregnancy test at screening or during the study, or woman who are breastfeeding
• If sexually active, participants who lack appropriate contraceptive measures
• Drug or alcohol dependence within the last 6 months
• No email access
• Patients presenting with abnormal QT interval prolongation at screening or with a history of this (QTc at screening above 470ms)
• Patients who are currently, or have recently (within 3 months) been enrolled in another CTIMP.