Could Psilocybin Help Treat Anorexia? A Small Clinical Trial Suggests the Psychedelic May Make Patients More Open to Recovery

Midway through therapy sessions with psilocybin, the psychoactive compound in “magic mushrooms,” some research participants diagnosed with anorexia asked for something unexpected: food. The trial, led by scientists at Imperial College London, was exploring whether the powerful psychedelic could be used to treat the eating disorder, which often results in patients limiting the amount of food they consume.

In other studies, such a request might be seen as a distraction, and the researchers might discourage it. “But in eating disorders,” says Jennifer Danby, the trial’s lead therapist, “allowing people to experiment with food in the room was a really important piece. Sometimes they were able to taste something and think, ‘Oh, it feels good to eat when I’m hungry,’ or, ‘It feels good to allow myself to eat something I wouldn’t typically eat.’ We were actively working with people’s relationship with food.”

The small trial’s results, published July 8 in The British Journal of Psychiatry, offer preliminary evidence that psilocybin, when paired with intensive psychological support, may help patients reckon with eating disorders. At the end of the six-week treatment period, 18 of the 21 participants showed an improvement in eating disorder symptoms.

“No treatment that we currently have is effective enough for enough people,” says Danby, who has worked with people with eating disorders for more than 15 years. Psychedelics, the study hints, could offer a new option for addressing one of psychiatry’s most difficult-to-treat conditions.

Psilocybin has previously produced promising results in clinical trials for depression, post-traumatic stress disorder, alcohol use disorder and anxiety. During these experiments, participants typically receive one or a few doses of the drug during guided sessions, with therapists providing preparation beforehand and helping them talk through their experience afterward.

Psychiatrists and neuroscientists have often speculated about other conditions that psychedelics could be used to treat. Anorexia nervosa has been a longstanding candidate: In 1959, a French psychiatrist reported treating a woman with anorexia by using psilocybin, and a 2023 American pilot study found psilocybin was associated with improvements in some, but not all, of ten female participants with anorexia. But the recent research is now the largest published clinical study of its kind, which will likely encourage even bigger trials in the coming years.

According to Danby, psilocybin is well-suited for treating one of anorexia’s defining features: rigid thinking. Patients often develop inflexible rules around food and exercise, struggle to tolerate uncertainty and find it difficult to imagine life without the disorder. “Typically, people have very black-and-white thinking,” says Danby. Psychedelics, by contrast, can “open up the ability to think, to see things in different ways, to have different perspectives and to have insight,” she adds. Even a temporary loosening of those patterns might make patients more receptive to recovery.

When early psilocybin studies suggested that the drug might disrupt rigid thinking in depression patients, Claire Foldi, a physiology researcher at Australia’s Monash University, saw a parallel with the inflexible, rule-bound behavior observed in rats she had used to model anorexia. “The overlap was hard to ignore,” she says. Beyond simply assuming that “psilocybin helps psychiatric illness generally, [so] why not this one too,” Foldi hypothesized that the drug might target cognitive rigidity across disorders.

Foldi has suggested that psilocybin may produce the “improvements in cognitive flexibility or decision-making … necessary for a therapeutic effect” in patients with anorexia. In a 2024 study, her team tested this possibility in groups of female rats. They restricted the rats’ food and allowed them to voluntarily access a running wheel to model symptoms of anorexia. In one group, psilocybin helped the rats maintain their weight. In a second group, the drug improved the rodents’ ability to adapt when researchers changed which action produced a food reward—an experimental measure of cognitive flexibility.

However, psilocybin has not yet been rigorously shown to be an effective treatment for anorexia in humans. “Rodent work establishes mechanisms” for how the substance could affect the brains of anorexia patients, Foldi says. “Human trials establish how much of the effect depends on the surrounding psychological scaffolding.”

The recent clinical trial enrolled 21 women whose anorexia had persisted for more than three years—11 years on average—and who had not experienced long-term remission despite previous treatment. Each participant had to enlist a family member or close friend for support and be under the care of a specialist eating-disorder service from the National Health Service, the publicly funded health care system in the United Kingdom.

To prepare for their psilocybin sessions, participants completed a series of calls and in-person meetings with a psychiatrist and a therapist. Because anorexia often centers on control, while psychedelic experiences may require people to surrender control, trying to build a strong therapeutic alliance before dosing was essential, Danby says.

The dosing itself took place across three sessions, each separated by two weeks. Participants began with a one-milligram dose of synthetic psilocybin in the initial session, followed by a 25-milligram dose in each of the two remaining sessions. Each time, the women reclined with eye masks and listened through headphones to a specially designed playlist. They entered with a goal they wanted to achieve during the session, but therapists encouraged them to hold it lightly, since the drug might take them in an unexpected direction.

Participants’ experiences varied considerably. According to Danby, some turned inward and needed little intervention; others became frightened and required sustained reassurance or physical support. The therapists followed the patients rather than steering them toward a predetermined insight. “We didn’t have an agenda about what we wanted people to get out of each experience,” Danby adds. “That was very much left to them.”

In psychedelic practice, patients are often advised to go “in and through” the effects of the drug—if fear or panic arises, they are encouraged to surrender to the feeling and see where it leads. For patients with anorexia, however, this approach could reproduce a familiar and counterproductive dynamic. The illness can function as a survival strategy, Danby says, and the harder clinicians push patients to relinquish control, the more tightly they may hold on. “We didn’t want it to become a battle,” she says.

So therapists encouraged participants to examine the resistant emotions or even try to feel them more intensely. “‘Why don’t we lean into the resistance? Why don’t we look underneath it?’” Danby recalls asking. “When somebody might say, ‘I’m really scared,’ then I might say, ‘Okay, let’s explore the fear.’”

After their sessions, participants met with their therapists to discuss the insights from their experiences and explore how they might translate into their daily lives. Anorexia may become the center of a patient’s life, especially in long-term cases. Effective treatments focus on helping people gradually rewrite the habits and attitudes that have been built up around the illness. Psilocybin could make patients more open to change and suggest new directions for recovery. But unless patients return to families and clinical teams prepared to support those tentative changes, says Danby, that opening could quickly close.

The results reflect this complicated trajectory. Nearly all participants showed initial improvements in symptoms, and across the group, self-reported symptoms remained lower after one year. Participants reported that they were more willing to acknowledge the seriousness of their illness and consider recovery.

However, improvements varied among participants and were not always maintained. Their BMIs did not change meaningfully during the six weeks they were monitored, though that wasn’t necessarily the goal—the trial included no nutritional intervention or explicit focus on weight restoration. Most side effects were mild or moderate; headaches and nausea were the most common. One participant attempted suicide twice, seven and nine months after dosing; however, suicide rates among people with anorexia are already high at baseline, and investigators concluded that the attempts were unlikely to be related to psilocybin.

The study is limited by the low diversity of its participant pool—16 of the 21 participants were white and British—as well as the lack of a separate placebo or control group, which makes it difficult to disentangle the influence of the roughly 50 hours of therapeutic contact that participants received. 

“Further research is needed to assess how these findings might apply to a broader, more diverse population,” Hannah Douglass, the paper’s lead author and a doctoral student at Imperial during the study, says in a statement. She calls the results encouraging but preliminary.

Danby cautions against thinking of the drug as a magic pill. “You take psilocybin and you have chronic anorexia. You still wake up in a malnourished body with huge mountains to climb,” she says. It is difficult for patients to form even minimal habits that would improve their well-being and mark small steps toward recovery. Rather than triggering sudden relief from symptoms, the benefit of psilocybin may lie in opening a window in which patients can make progress through “micro” changes—such as allowing themselves to wear a coat when they feel cold.

Larger, controlled trials will be needed to determine whether psilocybin can reliably create that opening. “Even a little bit more flexibility is a good thing,” Danby says.