Summary: Researchers used an innovative, remotely controlled vibrating capsule to identify indicators of relapse risk in people recovering from anorexia nervosa. The study shows these individuals have altered interoception—the ability to accurately sense, process, and trust internal gut sensations—which remains disrupted even after weight is restored.
The research team evaluated 62 females who had been hospitalized for anorexia nervosa and had achieved weight restoration, comparing them with 57 healthy controls. While an ingestible capsule delivered gentle stomach vibrations, investigators recorded brain, heart, and gastric rhythms. Participants pressed a button when they felt a sensation. Results showed that those recovering from anorexia nervosa were significantly less accurate at detecting internal bodily cues and often operated with a neural expectation that no sensation would occur.
Participants whose nervous systems were most biased toward ignoring visceral signals were at the highest risk of clinical relapse during a six-month follow-up. Because these gut–brain communication differences persist beyond weight recovery, the measured interoceptive markers may serve as objective biomarkers to help clinicians monitor treatment response and protect patients during recovery.
Key Facts
- High relapse rates: Up to 50% of people treated for anorexia nervosa relapse within one year after restoring body weight.
- Vibrating capsule trial: An ingestible wireless capsule delivered controlled mechanical vibrations to the stomach lining, allowing real-time measurement of physiological responses without using food.
- Altered interoception circuits: Differences reflect how the nervous system processes gastric sensations, not a conscious decision to ignore internal cues.
- Predicting relapse: A pronounced bias toward discounting gut signals was directly associated with higher relapse risk over six months.
- Persistence beyond weight: Disrupted gut–brain signaling remained evident even after patients reached a healthy weight.
- Biomarker potential: Computational measures of gut–brain function could provide clinicians with objective tools for risk assessment and personalized relapse prevention.
Source: UCLA
A vibrating pill could help clinicians assess relapse risk in anorexia nervosa, according to a new UCLA Health study.
Anorexia nervosa is a severe psychiatric disorder marked by persistent food restriction, intense fear of weight gain, and distorted body image, often resulting in dangerously low body weight. Relapse is common: up to half of patients experience clinical relapse within a year of successful weight restoration. The disorder also carries a high mortality rate, with suicide a leading cause of death.
Weight restoration is a primary goal of treatment, but many patients continue to struggle after reaching a healthy weight. The biological mechanisms that sustain symptoms and promote relapse are not well understood, and clinicians lack scalable, objective measures to track recovery beyond body mass index.
In a study published in JAMA Psychiatry, UCLA researchers used an ingestible vibrating capsule to probe gastrointestinal interoception and to evaluate whether gut–brain measures predict relapse in weight-restored patients with anorexia nervosa.
“People with anorexia nervosa don’t simply choose to ignore bodily signals,” said senior author Dr. Sahib Khalsa, psychiatrist and neuroscientist at the UCLA Semel Institute. “Rather, their nervous systems appear to process gut sensations differently, making those signals harder to detect, trust, and learn from. Over time, this altered interoception may help sustain symptoms even after weight is restored.”
The study enrolled 62 females with a history of restrictive anorexia nervosa who had regained healthy weight, alongside 57 age- and sex-matched healthy comparators. Each participant swallowed a wireless capsule that produced controlled stomach vibrations at normal and enhanced intensities. During stimulation blocks, participants indicated detection by pressing a button. Researchers recorded electroencephalography, cardiac and gastric rhythms, and self-reported hunger and visceral sensations, then followed the anorexia nervosa group for six months after hospital discharge.
Using computational modeling, the team estimated participants’ prior expectations about feeling stomach sensations, the precision with which their brains relied on incoming signals, and how quickly they updated expectations when signals appeared or did not appear. Compared with healthy controls, participants with anorexia nervosa showed reduced perceptual accuracy, higher miss rates, stronger expectations that no vibration would occur, and slower updating when stomach signals were present.
“In many cases, individuals with anorexia nervosa seemed to approach the task expecting not to feel gut signals and were less likely to revise that belief when sensations occurred,” Khalsa explained.
Crucially, several of these interoceptive markers predicted relapse over the subsequent six months. Those with the strongest bias toward discounting stomach sensations were more likely to experience clinical relapse. The study also found differences in how stimulation influenced hunger ratings, with larger hunger increases in the anorexia nervosa group.
Khalsa and colleagues emphasize that these gut–brain measures could eventually function as objective biomarkers to identify patients at higher relapse risk and to monitor whether targeted therapies restore healthy interoceptive processing. Potential interventions include interoceptive exposure, biofeedback, and treatments that directly target brain–body signaling, tailored to the individual’s specific processing deficits.
The researchers caution that findings must be replicated in larger and more diverse samples before clinical implementation. Still, the study supports the use of ingestible mechanosensory probes combined with computational modeling as scalable tools to improve relapse prediction and guide personalized recovery strategies in eating disorders.
Key Questions Answered:
A: Anorexia nervosa involves disrupted interoception—the brain’s internal mapping of bodily sensations—and the stomach is a major source of those signals. The ingestible capsule lets researchers deliver precise mechanical stimulation to the gut without food, which can provoke anxiety, enabling direct and objective measurement of how the nervous system detects and processes visceral input.
A: This phrase describes a pattern of neural processing rather than a conscious choice. Computational modeling showed that many participants with anorexia nervosa held strong prior expectations that the stomach would be inactive. When vibrations occurred, their brains were less likely to update those expectations, effectively filtering out real stomach sensations.
A: Currently, weight restoration is a common short-term recovery marker, but it does not guarantee restored brain–body communication. The vibrating capsule could be used at discharge to identify patients whose interoceptive circuits remain disrupted. Those patients could then receive targeted therapies—such as interoceptive exposure or biofeedback—to address sensory biases and lower relapse risk.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- The journal paper was reviewed in full.
- Additional context was added by editorial staff.
About this neuropharmacology and eating disorders research news
Author: Will Houston
Source: UCLA
Contact: Will Houston – UCLA
Image: Image credit: Neuroscience News
Original Research: Open access. “Altered Gastrointestinal Interoception in Anorexia Nervosa Predicts Relapse” by Verdonk C, Mink K, Choquette E, Moseman SE, Mayeli A, Stewart JL, Paulus MP, Smith R, Khalsa SS. JAMA Psychiatry. DOI: 10.1001/jamapsychiatry.2026.1301
Abstract
Altered Gastrointestinal Interoception in Anorexia Nervosa Predicts Relapse
Importance
Anorexia nervosa (AN) is a life-threatening psychiatric disorder with relapse rates approaching 50% after weight restoration. Disrupted gastrointestinal interoception may contribute to persistent symptoms and vulnerability to relapse.
Objective
To assess behavioral, computational, neural, and physiological markers of gastrointestinal interoception in weight-restored individuals with AN and to test their association with relapse.
Design, Setting, and Participants
This single-blind, within-participant, randomized crossover trial was conducted at the Laureate Institute for Brain Research between August 2021 and February 2025. Female participants with weight-restored restrictive AN and age- and sex-matched healthy comparators ingested a vibrating capsule that delivered counterbalanced blocks of normal- and enhanced-intensity gut stimulation. Outcome measures included behavioral detection, electroencephalography, peripheral physiology, and computational modeling of interoceptive processes.
Main Outcomes and Measures
Experimental-session outcomes included interoceptive accuracy, prior beliefs, interoceptive precision, learning rates, gastric-evoked potentials (GEPs), and hunger. Clinical outcomes at six months included relapse status and symptom severity.
Results
The cohort consisted of 62 females with weight-restored restrictive AN (mean age 18.9 years) and 57 healthy comparators (mean age 20.7 years). Six-month follow-up was available for 54 participants with AN. Compared with controls, the AN group showed lower perceptual accuracy and higher miss rates. Computational modeling indicated stronger prior expectations that vibrations would not occur, greater shifts in interoceptive precision between blocks, and asymmetric learning rates. GEP amplitudes were correlated with accuracy and learning in the AN group. Capsule stimulation produced larger increases in reported hunger among participants with AN.
At follow-up, relapse was predicted by initial priors, response bias, and stomach unpleasantness, while eating disorder symptom severity was predicted by miss rate, differences in interoceptive precision, and initial priors.
Conclusions and Relevance
In weight-restored females with AN, gastrointestinal interoception was disrupted across multiple domains—reduced accuracy detecting gut signals, maladaptive prior expectations, rigid learning, and altered hunger responses. Several interoceptive markers predicted relapse and symptom severity at follow-up. These results support the use of ingestible mechanosensory probes and computational modeling as scalable tools to monitor treatment response and guide relapse prevention in eating disorders.
Trial Registration
ClinicalTrials.gov Identifier: NCT05111977