Trial finds psilocybin to be a promising treatment for anorexia
A new phase 1 clinical trial has found that a single dose of psilocybin combined with psychotherapy may be a promising treatment for anorexia nervosa, a mental illness that is notoriously difficult to treat and for which there are currently no approved medications.
The mental health benefits of psilocybin, the main psychoactive ingredient in magic mushrooms, continue to be explored in clinical trials. There have already been trials testing psilocybin-assisted psychotherapy as a treatment for depression and anxiety, and now a new clinical trial has examined whether the drug is effective at treating anorexia nervosa.
Normally developing during adolescence, anorexia nervosa (AN) is characterized by excessive and undue preoccupation, fear and distress around food, weight, body shape and eating. It can lead to starvation, malnutrition, severe mental distress, and suicidal thoughts. Affecting AN can be difficult to treat and has one of the highest mortality rates of any psychiatric illness. There are currently no medications approved to treat the condition.
So, researchers from UC San Diego and the University of Michigan Medical School embarked on a phase 1 clinical trial to assess the safety, tolerability and efficacy of a single dose of synthetic psilocybin administered alongside psychological support to 10 females aged 18 to 40 with anorexia.
Psilocybin is thought to act on serotonin receptors, the body’s natural mood stabilizer, controlling happiness and well-being. Studies have shown that people with AN have altered brain serotonin function, suggesting that the condition may respond positively to treatment with psilocybin. In addition, the openness and self-acceptance that usually accompanies psilocybin treatment may shift existing thoughts around body image and food and lead to new attitudes.
After being given a single dose of 25 mg of psilocybin and engaging in psychotherapy, trial participants were assessed for three months. To evaluate the safety of the treatment, the researchers monitored participants’ vital signs, electrocardiograms (ECGs), laboratory tests and suicidal thoughts. They also assessed changes in the participants' self-reported body weight, shape, and eating concerns using the Eating Disorder Examination (EDE) questionnaire.
The researchers found that all women tolerated the psilocybin; no serious adverse events were observed besides mild and transient headache, nausea and fatigue. There was no increase in suicidal thoughts among the participants.
Most participants reported positive changes three months after receiving the psilocybin, including significantly reduced weight concerns after three months. Shape concerns decreased significantly at one-month follow-up but were no longer significant at three months. While the effects of psilocybin were highly variable, four participants – 40% of the sample – demonstrated substantial decreases in EDE scores after three months, qualifying for remission from an eating disorder.
Overall, the participants regarded the psilocybin experience as meaningful, with 90% saying they felt more positive about life endeavors and 70% reporting an overall shift in personal identity and quality of life. Notably, 90% of participants considered that a single psilocybin dosing session was not enough.
Reactions to the study from the wider research community have generally been positive.
“Novel treatment strategies are urgently needed for anorexia nervosa, which is associated with one of the highest mortality rates of any psychiatric condition, but until now, there was concern of specific risks of adverse effects in these individuals based on the medical abnormalities of low body weight and cardiovascular complications,” said Claire Foldi, a senior research fellow at Monash University’s Biomedicine Discovery Institute. “[T]he results offer promise in the pursuit of larger, adequately controlled trials that will determine whether psilocybin-assisted psychotherapy could aid in the unmet need for effective treatment options for individuals suffering from anorexia nervosa.”
Marion Roberts, a clinical psychologist and lecturer at the University of Auckland’s Faculty of Medical and Health Sciences, was also supportive of the study, saying, “With current treatments only successful for a minority of adult patients, it is highly appropriate that the field is thinking creatively – in this case, the use of psychedelics. These early yet promising findings certainly merit further investigation.”
But others warned against getting caught up in the hype around psychedelics.
“Psilocybin therapy has provided glimmers of hope in other mental health disorders, notably by providing evidence that it can improve anxiety, cognitive flexibility, and self-acceptance for some people,” said Trevor Steward, a senior research fellow in the School of Psychological Sciences at the University of Melbourne. “However, this study does not demonstrate that psilocybin therapy can be used to treat anorexia nervosa … While these results show this psilocybin therapy is safe under controlled conditions, it’s essential not to let the hype around psychedelics outpace the scientific evidence. Continued research and caution are of the utmost importance to ensure we make informed decisions about the potential of psilocybin therapy in tackling this deadly illness.”
The researchers note that their study has limitations. It had a small, self-referred sample size that did not include a placebo group. They say that although the psilocybin therapy was well tolerated, further randomized controlled trials are needed to validate their findings.
The study was published in the journal Nature Medicine.