Overview
PsiAN is a clinical trial based in Lund, Sweden, investigating whether psilocybin, given
together with psychological support, can be a safe and helpful treatment for young adults with
anorexia nervosa (AN).
⚠️ Important: It is not possible to register for participation in the study here.
What is Anorexia Nervosa?
Anorexia nervosa (AN) is a serious eating disorder characterized by restricted energy intake,
distorted body image, and intense fear of weight gain. AN is known to have the highest mortality rate among psychiatric disorders and currently lacks any pharmacological treatment.
Diagnostic criteria
ICD-11 (6B80, Anorexia nervosa):
- Persistent restriction of energy intake, leading to significantly low body weight.
- Intense fear of weight gain or persistent behavior preventing weight gain.
- Distorted body image or lack of recognition of seriousness of low body weight.
- In children/adolescents: failure to achieve expected weight gain or growth.
DSM-5 (307.1, Anorexia nervosa):
- Restriction of energy intake relative to requirements, leading to significantly low body
weight. - Intense fear of gaining weight or persistent behavior interfering with weight gain.
- Disturbance in self-perceived weight or shape, undue influence of body weight/shape
on self-evaluation, or denial of seriousness of low weight.
Clinicians often use a BMI below 18.5 as a guideline for adults, while in children and
adolescents weight is compared against growth charts.
In practice, BMI levels are used as supportive measures (for example, <17 or <16 to
indicate severity), but they are not part of the official diagnostic criteria—rather, they
serve as a clinical specification.
Severe and Enduring Eating Disorders (SEED) and SE-AN
Most individuals with eating disorders recover, but approximately 20% do not and instead
develop Severe and Enduring Eating Disorders (SEED).
SE-AN (Severe and Enduring Anorexia Nervosa) refers to patients with anorexia nervosa
lasting many years (often >7 years), with repeated relapses and persistent disability despite
standard treatment
- SE-AN is associated with the highest mortality rate among psychiatric disorders.
- Patients often experience severe medical complications (osteoporosis, infertility, cardiovascular problems) and psychosocial impairment.
- SE-AN accounts for a large share of healthcare costs for eating disorders, while treatment options remain very limited.
Psychedelics and Psilocybin
- Psychedelics are compounds that alter perception, mood, and cognition.
- Psilocybin is a naturally occurring psychedelic substance that acts on the serotonin 5-HT2A receptor.
- Neuroimaging shows that psilocybin can increase communication between brain networks and reduce rigid, maladaptive patterns of activity (such as overactive default mode network).
- Clinical studies have shown promising effects in depression and addiction, but research in eating disorders is still in its early stages.
The PsiAN Study
- Aim: Explore the safety, tolerability, and preliminary efficacy of psilocybin in young
adults with anorexia nervosa (ages 16–35). - Design: 40 participants, randomized into two groups:
- Psilocybin (25 mg, two sessions one month apart) with psychological support
- Standard treatment only (Treatment as Usual, TAU)
- Primary outcome: Safety and tolerability.
- Secondary outcomes: Eating disorder symptoms, relapse prevention, cognitive
flexibility, emotional insight, biomarkers (blood samples, BDNF), and brain imaging
(fMRI).
Ethics and Safety
Approved by the Swedish Ethical Review Authority and the Medical Products
Agency (Läkemedelsverket).
- Independent safety committee monitors all study data.
- Adolescents aged 16–17 will only be included after safety has been established in
adults and following committee approval. - Participation always includes informed consent, close medical monitoring, and professional psychological support.
Timeline
- 2024–2025: Regulatory approvals obtained ✔
- Autumn 2025: Focus group
- Autumn 2025: First participants enrolled
- 2026: Ongoing treatments and follow-ups
- 2027: Final analyses and publication of results
