Researchers at UCLA Health have developed an innovative approach that could help clinicians identify which patients recovering from anorexia nervosa are at greatest risk of relapse. Using an ingestible vibrating capsule to probe communication between the gut and the brain, the team found measurable differences in how people with anorexia process internal bodily signals. Differences that may persist even after weight restoration.
The findings provide new insights into the biological mechanisms underlying anorexia nervosa and may pave the way for objective biomarkers to guide treatment and long-term monitoring. Anorexia nervosa remains one of the most challenging psychiatric disorders to treat. While restoring body weight is a central goal of therapy, recovery often extends far beyond achieving a healthy weight. Relapse rates remain high, with up to half of patients experiencing a recurrence within a year of treatment.
According to Dr. Sahib Khalsa, psychiatrist, neuroscientist and senior author of the study, clinicians have long lacked objective tools to assess whether the underlying drivers of the disorder have truly improved. “Many patients continue to struggle even after reaching a healthy weight,” Khalsa explained. “Understanding how the brain interprets signals from the body may help explain why relapse remains so common.”
A capsule that talks to the gut
To investigate this, researchers focused on interoception, the process by which the brain detects and interprets internal bodily sensations such as hunger, fullness and stomach activity. The study involved 62 women and adolescent girls who had recently completed inpatient treatment for anorexia nervosa and restored their weight, alongside 57 healthy control participants.
Each participant swallowed a remotely controlled vibrating capsule capable of generating gentle sensations inside the stomach. During the experiment, participants were asked to press a button whenever they detected a vibration. At the same time, researchers monitored brain activity, heart function and gastric rhythms while participants reported sensations such as hunger and stomach awareness.
The resulting data were analysed using computational models designed to assess how participants formed expectations about bodily sensations and how effectively they updated those expectations when new sensory information became available. The findings, published in JAMA Psychiatry, revealed clear differences between participants with anorexia nervosa and healthy controls. Individuals recovering from anorexia were less accurate at detecting subtle stomach sensations and were more likely to assume that no sensation was present, even when the capsule was actively vibrating. Perhaps more importantly, they were slower to revise these expectations when sensory signals did occur.
Predicting relapse
Researchers followed the anorexia participants for six months after hospital discharge. Several of the measured gut-brain communication patterns proved to be associated with relapse risk. Patients who showed the strongest tendency to ignore or discount stomach signals were more likely to experience a return of symptoms during follow-up.
The results suggest that anorexia may involve persistent alterations in how the nervous system processes internal bodily information. Rather than consciously disregarding hunger or fullness cues, patients may have difficulty accurately detecting and interpreting these signals in the first place. “One of the most striking findings was that these differences persisted even after weight restoration,” said Khalsa. “Recovery from anorexia nervosa is not simply about restoring body weight. The underlying brain-body communication challenges may remain and contribute to relapse.”
Digital biomarkers for eating disorders
The researchers believe these gut-brain measurements could eventually become clinically useful biomarkers, helping healthcare professionals identify patients who require closer follow-up after treatment. Such biomarkers could also be used to evaluate whether new therapies are successfully improving the brain’s ability to process internal bodily signals, potentially providing a more objective way to measure recovery than weight alone.
Although the findings are promising, the researchers emphasize that larger and more diverse studies will be needed before the technology can be translated into routine clinical practice. Nevertheless, the study highlights a growing trend in mental health research: the use of innovative technologies to better understand the biological foundations of psychiatric disorders. In the case of anorexia nervosa, a tiny vibrating capsule may offer a new window into the complex relationship between the brain, the body and long-term recovery.
