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The patient: A 60-year-old man in Seattle
The symptoms: The man experienced paranoia, as well as auditory and visual hallucinations. He was also very thirsty but was fearful of drinking water that others offered to him.
What happened next: The man went to an emergency department because he was worried that his neighbor poisoned him. Doctors checked his vital signs and conducted a neurological examination, which did not highlight any immediate concerns.
That changed when blood tests revealed that his level of chloride ions — charged particles of the element chlorine — were above the normal range. This result suggested that the patient may have been suffering from hyperchloremia , a condition in which chloride ions build up in the blood. This usually occurs in people who are dehydrated or consume too much salt.
However, when doctors measured the concentration of other ions in the patient's blood, they realized that this initial interpretation was wrong.
In patients with hyperchloremia, the body cancels out the increase in negatively charged chloride ions by depleting negatively charged bicarbonate ions, which the body makes itself. In essence, the body tries to regulate the electrical balance of the blood.
However, in the man's case, tests revealed that his blood was too negatively charged overall. The most likely explanation was that a negatively charged poison had built up too fast for his body to buffer the change by depleting other ions.
The diagnosis: The man's doctors consulted the poison control department and figured out that he was experiencing a case of pseudohyperchloremia, a condition in which the lab test for chloride erroneously detects another negatively charged ion. This makes it seem like a patient's chloride is too high while masking the actual problem.
A common culprit behind this phenomenon is a high dose of salicylate (aspirin) , but the patient didn't have high levels of this pain reliever in his blood.
The next suspect, and the more unusual one, was the poison bromide, a charged form of bromine. Bromine sits just below chlorine on the periodic table, meaning their ions share similar chemical properties, such as charge and size, and bromide has triggered the lab test for chloride in previous reports .
When the doctors measured the patient's bromide levels, they found that they were roughly 230 times higher than the normal range. They diagnosed him with bromide poisoning, also called bromism, which can cause neurological symptoms such as hallucinations and paranoia.
Taking high doses of aspirin can sometimes lead to pseudohyperchloremia, because lab tests for chloride detect the aspirin in a person's blood. In this case, though, aspirin was not the cause. (Image credit: boonchai wedmakawand viva Getty Images) The treatment: The patient remained in a hospital bed for three weeks so doctors could monitor and replenish his electrolytes. On account of his paranoia, he tried to escape from the hospital, so the doctors had to hold him there involuntarily. They gave him daily doses of risperidone, an antipsychotic medication.
His symptoms improved, and he was weaned off medication and ultimately discharged. His condition remained stable during a follow-up assessment two weeks later.
What makes the case unique: After his condition improved, the patient informed the doctors that he had searched for a healthier alternative to table salt (sodium chloride) and had consulted ChatGPT for advice. The chatbot suggested he swap sodium chloride with sodium bromide, and he experimented with that suggestion for three months.
Medicines containing bromide salts used to be popular for treating various conditions, such as headache or upset stomach . These medications fell out of common use when doctors realized that bromide accounted for 8% of admissions to psychiatric hospitals in the early 20th century.
Because it is similar in size and charge to chloride, bromide can fill in for chloride's roles in the body — and that's a problem. For example, chloride contributes to the brain's electrical activity by passing through chloride channels in neurons. Bromide can also move through these channels and thus disrupt normal brain activity, bringing about neurological symptoms .
Bromide poisoning is rare nowadays, so doctors don't typically assume that their patients experiencing paranoia or hallucinations could have this form of poisoning. However, bromide supplements can be easily purchased online, opening the door to such cases, the doctors wrote in a report of the case .
The man's doctors wanted to see whether ChatGPT would again point to bromide salts if asked the same question. They prompted the chatbot with queries about ways to remove chloride ions from the diet, and once again, the bot suggested bromide salt as an alternative. This response didn't provide a health warning about the dangers of consuming too much bromide.
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Given the willingness of chatbots to recommend bromide salts, the doctors argued in the report that it would be prudent to more seriously consider the possibility of bromism during psychological evaluations. This case highlights the dangers of relying on AI chatbots for medical advice , the doctors concluded.
Live Science contacted OpenAI, the developer of ChatGPT, about this case and is awaiting comment. According to the service terms at OpenAI, "You should always verify the information provided by ChatGPT for Healthcare and exercise independent professional judgment in decision-making about a patient without relying primarily or solely on the output."
( Live Science first covered this case when it was published in 2025, and at that time, an OpenAI spokesperson said that the company's safety teams were working to reduce the risk of using its services and to train its products to prompt users to seek professional advice.)
This article is for informational purposes only and is not meant to offer medical advice.
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