When Arsenic, Anorexia and PTSD Collide: A Rare Triple Diagnosis Stuns Doctors

A 33-year-old woman arrived at the gastroenterology ward of Peking Union Medical College Hospital with a constellation of symptoms that baffled her treating team: progressive diarrhea, darkening of the skin, swelling in her limbs, and numbness in both legs. None of these complaints pointed cleanly to a single diagnosis. What emerged over the course of her evaluation, however, was far stranger than any single illness. Clinicians eventually uncovered a rare triple comorbidity—anorexia nervosa, post-traumatic stress disorder, and chronic arsenic poisoning—linked together by the patient’s long-standing, secretive self-medication with arsenic-containing traditional remedies in pursuit of weight loss. The case, reported in the journal Discover Mental Health by a team from Peking Union Medical College Hospital, offers a striking window into how psychiatric and toxicological pathology can intertwine, delay diagnosis, and nearly cost a patient her life.

The clinical journey began with what appeared to be a straightforward gastroenterological workup. Chronic diarrhea, hyperpigmentation, edema, and peripheral neuropathy are classic hallmarks of chronic arsenic toxicity, a condition that remains endemic in parts of the world where groundwater contamination is prevalent. But this patient had no environmental exposure to speak of. The turning point came when clinicians pieced together her medication history: she had been persistently self-administering bisacodyl, a stimulant laxative, along with a traditional Chinese medicine known as the Bezoar Antidotal Pill. Laboratory analysis revealed that the pill contained microquantities of arsenic trioxide and arsenic pentoxide—two toxic arsenic compounds. Taken repeatedly over time, these small doses accumulated, producing the insidious poisoning that had finally driven her to seek care.

The motivation behind this dangerous regimen was the first psychiatric thread in the case. During a consultation-liaison psychiatry assessment, specialists diagnosed anorexia nervosa on the basis of the patient’s excessive preoccupation with weight and her deliberate use of laxatives and arsenic-laced pills to shed pounds. Anorexia nervosa is among the most lethal psychiatric disorders, and its hallmark features—intense fear of weight gain, distorted body image, and restrictive or purging behaviors—often drive patients toward increasingly hazardous methods of weight control. The use of toxic traditional medicines for slimming purposes is a documented but underrecognized phenomenon, particularly in regions where such remedies are widely available and perceived as natural or safe. In this patient, that perception collided catastrophically with the biological reality of cumulative arsenic toxicity.

Yet one aspect of her presentation did not fit the anorexia nervosa picture. Despite her skin darkening, diarrhea, and neurological symptoms—signs that any reasonable observer would find alarming—the patient had delayed seeking medical care for a remarkably long time. She only presented to the hospital when she became convinced that her physical condition was genuinely life-threatening. This pattern of self-neglect sat uneasily beside the intense body preoccupation characteristic of anorexia nervosa, which typically involves heightened, not diminished, attention to bodily signals. The discrepancy puzzled the liaison psychiatry team and prompted a deeper biopsychosocial interview, a decision that would prove decisive for both diagnosis and treatment planning.

That deeper interview revealed a history of post-traumatic stress disorder, and with it, the missing piece of the diagnostic puzzle. The researchers propose that the patient’s delayed presentation was a combined effect of two distinct psychological mechanisms: the denial commonly seen in anorexia nervosa, which minimizes the severity of physical harm, and the generalized avoidance that defines PTSD, which drives patients away from medical settings, memories, and anything reminiscent of past trauma. Rather than one disorder explaining the delay, the two conditions appeared to act synergistically, with PTSD exacerbating the pre-existing anorexia-related postponement of care. This formulation transformed a confusing clinical contradiction into a coherent biopsychosocial narrative, and it illustrates why single-diagnosis thinking can fail catastrophically in complex patients.

The comorbidity of eating disorders and post-traumatic stress disorder is well documented in the psychiatric literature, though it remains underdiagnosed in routine practice. Epidemiological studies have repeatedly shown that individuals with eating disorders report elevated rates of traumatic exposure and PTSD compared with the general population, and that trauma histories are associated with earlier onset, greater severity, and poorer outcomes in eating pathology. Shared mechanisms have been proposed, including emotion dysregulation, dissociation, and the use of eating behaviors as a means of coping with trauma-related distress. For some patients, controlling food and body weight becomes a maladaptive strategy for managing overwhelming internal states—a dynamic that may have been operating in this case, where weight loss efforts escalated to the point of self-poisoning.

The treatment implications of such comorbidity are substantial. The authors review current thinking on managing eating disorders and PTSD concurrently, noting that addressing one condition in isolation risks undermining progress on the other. In a liaison psychiatry setting, where psychiatric consultants work alongside medical teams, the challenge is compounded by the physical consequences of the eating disorder and, in this case, the toxic effects of arsenic. Chronic arsenic poisoning requires cessation of exposure and careful medical management of gastrointestinal, dermatological, and neurological complications, while the psychiatric conditions demand structured psychotherapy, nutritional rehabilitation, and attention to trauma-related symptoms. Coordinating these strands of care requires a team-based approach and a high index of suspicion for hidden psychiatric drivers of medical presentations.

The case also carries a broader public health message about traditional medicines. The Bezoar Antidotal Pill, a classical remedy, contains trace amounts of arsenic compounds that are generally harmless in occasional, properly dosed use but dangerous with persistent self-administration. Because patients often do not regard traditional preparations as medications, they may fail to disclose them during clinical interviews, leaving physicians blind to a critical source of toxicity. The authors’ report underscores the importance of explicitly asking about all supplements, herbal products, and traditional remedies—particularly in patients with unexplained multisystem symptoms such as hyperpigmentation, diarrhea, edema, and peripheral neuropathy, which together should always raise the question of chronic heavy metal exposure.

Ultimately, this report stands as a rare and instructive example of diagnostic medicine at its most demanding. A single patient carried three interacting conditions—an eating disorder that drove her toward toxic weight-loss agents, a trauma disorder that kept her away from help, and a heavy metal poisoning that was the direct consequence of both. The authors argue that recognizing the interplay among these conditions was essential to making her clinical picture rational and to planning meaningful treatment. For clinicians, the lesson is that puzzling inconsistencies in a patient’s story are often signals to look deeper rather than artifacts to dismiss. For the public, it is a sobering reminder that remedies marketed as natural can carry lethal doses, and that the pursuit of thinness, when entangled with untreated trauma, can push individuals into territory where the line between self-treatment and self-harm disappears entirely.

Subject of Research: A case report of co-occurring anorexia nervosa, PTSD, and chronic arsenic poisoning from arsenic-containing traditional medicine used for weight loss.

Article Title: Post-traumatic stress disorder and anorexia nervosa in a patient with chronic arsenic poisoning: a case report and review of literature

Article References: Ma, D., Xie, Y., Wang, Q., Tang, H., Fang, X., Cao, J., & Wei, J. (2026). Post-traumatic stress disorder and anorexia nervosa in a patient with chronic arsenic poisoning: a case report and review of literature. Discover Mental Health. https://doi.org/10.1007/s44192-026-00599-x

Image Credits: AI Generated

DOI: 10.1007/s44192-026-00599-x

Keywords: anorexia nervosa, post-traumatic stress disorder, chronic arsenic poisoning, eating disorders, consultation-liaison psychiatry, traditional Chinese medicine, delayed medical seeking, comorbidity, heavy metal toxicity, biopsychosocial interview, weight loss, case report