In brief
- A pilot trial at Imperial College London tested psilocybin with therapeutic support in 21 women with long-term anorexia nervosa (average duration of 11 years).
- 86% showed improvement at two weeks, and nearly half reached scores typical of people without an eating disorder at three months, with effects sustained at one year.
- This is one of the first studies to explore psychedelics outside of depression and PTSD, a largely uninvestigated area despite the extremely high mortality rate of anorexia.
A team at Imperial College London has published the results of a pilot trial in which synthetic psilocybin, combined with intensive therapy, was administered to women with anorexia nervosa who had been ill for an average of eleven years without finding a long-term effective treatment. The study, published on July 8, 2026, in the British Journal of Psychiatry, is small and lacks a control group, but it opens an almost unexplored avenue of research: the vast majority of psilocybin trials have focused on depression or post-traumatic stress disorder, not eating disorders.
A six-week protocol for a decade-long illness
The study included 21 adult women with an average age of 32 and an average body mass index of 16.4 (below the healthy threshold of 18.5). The protocol, led by researcher Hannah Douglass alongside the team of Robin Carhart-Harris and David Erritzoe, consisted of three dosing sessions separated by two weeks: the first with 1 mg, intended as a nearly inactive reference dose, and the following two with 25 mg each. Each session was accompanied by hours of therapeutic conversation before and after, led by psychotherapist Jennifer Danby, who specializes in eating disorders. Participants were blinded to the dosage they received at any given time.
Improvements maintained up to a year later
Two weeks after the final session, 18 of the 21 women (86%) showed improvement in their eating disorder symptom scores. At three months, 48% presented values comparable to those of people without a diagnosis. At six months, the effect remained, and at one year, participants reported maintaining greater motivation to pursue recovery, although body weight barely changed during the six weeks it was measured. The most common adverse effects were headache and nausea. One participant attempted suicide between the seventh and ninth months of follow-up; the research team considered the episode unrelated to the intervention, though they reported it with transparency given the high risk of suicide associated with long-term anorexia, even outside of any treatment. Another participant dropped out of the study after the second dose.
What this implies
The authors themselves emphasize caution: the sample is small, there was no real placebo group to isolate the specific effect of the substance from the nearly fifty hours of accompanying therapy, and the population was not very diverse (16 of the 21 participants were white British). Carhart-Harris summarizes it as “a pioneering trial with promising results that justify larger and more rigorous studies.” Erritzoe also highlights something that connects to any serious discussion about harm reduction with psychedelics: in complex clinical presentations like this, support must be provided by trained clinicians in a supportive environment, not improvised. Anorexia nervosa has one of the highest mortality rates among mental disorders, and a significant portion of those who suffer from it chronically do not respond to available treatments, which explains the interest in exploring alternatives, including less conventional pharmacological ones, without presenting them as a definitive solution or minimizing the risks for an especially vulnerable clinical population.
Source
- Imperial College London. Psilocybin therapy shows potential as a treatment for anorexia nervosa in small trial. Imperial College London News, July 8, 2026.
Educational content written from a harm reduction perspective and with respect for individual freedom. It is not a substitute for advice from a healthcare professional and is not intended to encourage or condemn any drug use.
