A vibrating pill could help doctors determine if a patient with anorexia nervosa may have a higher risk of relapse, according to a new study by UCLA Health on June 17.
Anorexia nervosa is described as a psychiatric disorder marked by persistent restriction of food intake, fear of gaining weight, and distorted body image. The condition often leads to significantly low body weight and has one of the highest mortality rates among psychiatric disorders, with suicide being the leading cause of death. Relapse rates for those treated for anorexia nervosa remain high, reaching up to 50% within one year after restoring body weight.
Although achieving healthy body weight is central to treatment, many patients continue to struggle after this milestone. The mechanisms underlying the disorder are not well understood, and there is currently a lack of objective biomarkers for tracking patient response during recovery.
In research published in JAMA Psychiatry, UCLA researchers used an ingestible vibrating capsule to predict relapse risk and explore how anorexia affects the nervous system. The team led by Khalsa recruited 62 women and girls hospitalized with anorexia whose weights had been restored and compared them with 57 healthy controls. Participants swallowed a remotely controlled vibrating capsule that produced gentle stomach sensations at varying intensities. They were instructed to press a button when they felt vibrations while researchers monitored brain, heart, and stomach activity. Participants also reported their hunger levels and other bodily sensations before follow-up evaluations over six months post-discharge.
Analysis using computational models showed that individuals with anorexia were less accurate at detecting subtle stomach sensations than healthy participants. They were more likely to believe no sensation was occurring even when the pill vibrated, and slower in updating their expectations when signals changed. "In essence, some individuals with anorexia nervosa appeared to enter the task expecting not to feel signals from the gut and were less likely to update those expectations when signals occurred," Khalsa said.
Several gut-brain measures tracked during the study correlated with increased relapse risk during follow-up; participants whose perception was biased toward ignoring gut signals relapsed more frequently. "One of the most striking findings was that these differences persisted even after weight restoration," Khalsa said. "Recovery from anorexia nervosa isn't just about restoring body weight. The underlying brain-body communication problems may remain and could contribute to relapse." Khalsa said these measures might eventually serve as biomarkers for identifying patients at higher risk or monitoring treatment progress, but noted further studies are needed in broader populations.
