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Psilocybin Has Outstanding Success Treating Anorexia Nervosa In First Very Small Trial

There were only ten participants and no control group, but the results were still outstandingly hopeful.


Stephen Luntz


Stephen Luntz

Freelance Writer

Stephen has a science degree with a major in physics, an arts degree with majors in English Literature and History and Philosophy of Science and a Graduate Diploma in Science Communication.

Freelance Writer

blue gloved hand picking up magic mushroom from dish with tweezers, psychedelic effect applied

Four participants later were in remission.

Image Credit: 24K-Production/

A single dose of psilocybin, taken in a safe therapeutic environment, was all it took to put four women with anorexia nervosa into remission three months later in a new study. Most other participants also said they had benefited from the treatment. Far more extensive trials are needed before the viability of the treatment can be confirmed, but considering how devastating the effects of anorexia can be, and the limited success of existing treatments, the potential looks remarkable. 

However, like all research on psilocybin, progress is likely to be slow as long as most politicians would rather prosecute people for using the drug than see them treated with it. For decades, people who take psilocybin, the active ingredient in magic mushrooms, have promoted its potential to treat a variety of mental health conditions. In most countries, however, research on the topic was illegal, or almost so, leaving no way to move from anecdotes to high-quality evidence.


Determined researchers have found ways to skirt the laws, and some countries have slowly eased restrictions, but the sort of large-scale randomized controlled trials used for other drugs remain rare. In such a tough environment, conditions like anorexia have been at the back of the queue to be studied, but things have changed enough that Dr Stephanie Peck and colleagues at the University of California, San Diego have now managed to conduct a study of ten women aged 18-40 with anorexia that had lasted an average of nine years pre-trial.

The participants were given a single 25mg dose of COMP360 psilocybin, a synthetic form specifically designed for research. This was administered in a safe environment with psychological support – no one should assume that self-medicating in an unsupported environment would produce the same results.

Although side effects such as headache and nausea were common, all resolved quickly and none were serious. Four participants experienced such dramatic improvements that three months later they were assessed as being in remission. Of the other six, three said their overall quality of life had improved, and five of the other six who were not in remission felt more optimistic. Only one indicated she was not keen to take a further dose.

The authors acknowledge the sample size and lack of a control group limit the conclusions that can be drawn. Nevertheless, the results need to be seen in the context of the poor success rates for existing treatments. Talk therapies only produce full recoveries for about a quarter of patients and 20 percent of those diagnosed with anorexia have reduced life expectancy as a result. As it's been estimated that around 4 percent of women will have anorexia at some point, that potentially means around 0.8 percent of women in developed countries are dying early, often decades early, because we lack an effective way to treat the condition.


Trials of transcranial magnetic stimulation have also been promising, but besides the fact that these are also in an early stage, TMS is an expensive program, unaffordable to many in countries where it is not fully funded.

"It is exciting to see this research being undertaken. There are currently no approved pharmacological interventions for anorexia nervosa and these are very much needed to save lives!,” said Professor Gemma Sharp, an expert in eating disorders at Monash University, who was not involved in the study, in a statement

Sharp and other researchers who commented, as well as the authors themselves, all stressed the preliminary nature of the research.

Australia recently became the first country to legalize psilocybin, along with MDMA, as a treatment for depression, which should ease access for other conditions.


The study is published in Nature Medicine 

If you or someone you know might have an eating disorder, help and support are available in the US at In the UK, help and support are available at International helplines can be found at      


healthHealth and Medicinehealthneuroscience
  • tag
  • mental illness,

  • psilocybin,

  • neuroscience,

  • psychedelics,

  • eating disorder,

  • Anorexia nervosa