Anorexia is one of the most common mental illnesses in young women - and one of the most persistent. Because common psychotherapies do not work for many of those affected and there are no medications. For this reason, researchers have now tested the psychoactive drug psilocybin as a therapy aid in a clinical study for the first time. Ten women suffering from anorexia nervosa received a one-off dose of the substance known from "Magic Mushrooms" and received additional psychological care. As a result, the vast majority of participants reported a subjective improvement, with some also able to demonstrate this in objective tests. The team believes this is promising enough to investigate this form of therapy in further studies.
Anorexia is an eating disorder that affects an average of 1.4 percent of women worldwide. Typically, they hardly eat any more and try to avoid weight gain by using methods such as taking laxatives or exercising excessively. This is due to a disturbed body image: people with anorexia nervosa still feel too fat even when they are already extremely emaciated - and that can have fatal consequences. The risk of dying as a result of organ damage and malnutrition is 18 times higher than that of healthy people. However, what triggers this eating disorder is largely unknown. It is assumed that the combination of predisposition and prenatal and early childhood influencing factors increases the susceptibility to anorexia. So far, attempts have been made to help the sick primarily with psychotherapy. However, this only works to a limited extent: around half of those affected relapse, and 20 percent develop chronic anorexia. So far there are no effective drugs.
Drug acts on serotonin balance
This is where a clinical study comes in, in which Stephanie Knatz Peck from the University of California in San Diego and her team tested what at first glance seemed an unusual treatment method: They administered the psychoactive drug psilocybin to their ten anorexic test subjects. This substance, produced by some fungi, is converted to its bioactive form, psilocin, in the body and also makes its way to the brain. There it binds to the docking point of the neurotransmitter serotonin and thereby activates the type 2A serotonin receptors in particular. This causes changes in consciousness similar to LSD and can induce hallucinations. At the same time, psilocybin influences the plasticity of synaptic connections and can thereby promote the formation of new connections in the brain. Studies show that a small dose of this "magic mushroom" drug can also be therapeutically effective: Psilocybin had a lasting alleviating effect in people with severe depression and obsessive-compulsive disorder.
Based on these experiences, Knatz Peck and her colleagues wanted to investigate whether psilocybin might also help with anorexia. "There is some evidence that people with anorexia nervosa have an altered function of the serotonin receptor 2A in the brain," the researchers explain. "This supports the assumption that the effect of psilocybin on this receptor can also have a positive effect on the symptoms of anorexia." In addition, the obsession of the mostly female sufferers also has traits of an obsessive-compulsive disorder - they often find it extremely difficult, even with psychotherapeutic help, to change their rigid self-view, their routines and ways of thinking. With their phase 1 study, Knatz Peck and her colleagues primarily wanted to test whether the fungal drug is well tolerated by anorexia sufferers and what side effects it has. But they also examined possible positive effects on the subjective well-being and condition of the participants.
Positive effects verifiable
Ten women took part in the study, most of whom had been suffering from anorexia for several years and were therefore clearly underweight. Five of them had previously attempted to overcome their anorexia with the help of psychotherapeutic treatment, but had fully or partially relapsed. Seven of the women suffered from an accompanying depression, three also had an obsessive-compulsive disorder. In the two weeks prior to the psilocybin administration, the subjects underwent a thorough psychological examination on two dates and were prepared for the study procedure. Then the women took 25 milligrams of pure psilocybin in the form of capsules and were intensively cared for by psychologists in the clinic during the roughly eight-hour phase of the acute drug symptoms. Side effects were also recorded. Then they were allowed to go home. The next day and one week later, all participants completed a 60- to 90-minute psychotherapy session. In addition, after one week and after one and three months, they were examined psychologically and physically in detail and asked about their subjective well-being in order to assess the effect of psilocybin on anorexia.
The evaluations showed that psilocybin was tolerated by the anorexic women without serious side effects. At the same time, most participants stated that they had noticed positive changes in themselves. "90 percent had a more positive feeling about the challenges of life, 80 percent even described the experience as one of the five most important of their lives," report Knatz Peck and her team. 70 percent of the women felt a general improvement in their quality of life. However, the objective results were significantly more variable and less clear, for example in the psychological assessment of the anorexia indicators and the physical parameters. On average, psilocybin administration resulted in significant improvements in parameters such as anxiety generated by distorted body image and obsession with diet, shape and food. At the same time, the team was only able to determine a lasting improvement in the values of the established eating disorder examination in only four test subjects even after three months.
Further studies useful
Nevertheless, Knatz Peck and her colleagues see the results of their preliminary study as positive: "Most of the participants reported subjective improvement even three months after the psilocybin administration," they write. "The fact that the treatment was considered positively effective by most test subjects and that there were no dropouts are promising indications." It is also noteworthy that a subgroup of the participants showed positive effects after a single dose of psilocybin - this is often not the case with classic anorexia therapies, even after a long time. The researchers therefore think it makes sense to carry out further and more extensive studies on the therapeutic effects of psilocybin in anorexia. Tomislav Majic from the Charité Universitätsmedizin Berlin and Stefan Ehrlich from the Technical University of Dresden take a similar view. In an accompanying commentary, they write, "Given the need for effective and acceptable therapies for this disorder, psilocybin therapy may hold promise for further clinical evaluation."
Source: Stephanie Knatz Peck (University of California, San Diego) et al., Nature Medicine, doi: 10.1038/s41591-023-02455-9