​​Mom Cries as She Learns 12-Year-Old Daughter’s Death by ‘Acute Psychosis’ Was Actually Caused by Rare Brain Disorder

Undiagnosed Autoimmune Brain Disorder Linked to Death of 12-Year-Old in U.K. Psychiatric Unit, Inquest Hears

A mother broke down in tears this week as she learned that her 12-year-old daughter, who died in a psychiatric unit in England last year, had been suffering from a rare but potentially treatable brain disorder that may have driven her behavior.

On Monday, Nov. 24, new evidence presented at a hearing at Sheffield Coroner’s Court showed that Mia Lucas had autoimmune encephalitis (AE), according to reports from the BBC, ITV and YorkshireLive.

The inquest, which began last week, is examining whether this condition contributed to Mia’s death.

Nearly two years ago, Mia began hearing voices telling her to harm herself and tried to get knives from the kitchen, leading to her admission to the Becton Centre in Sheffield. She was found unresponsive in her room on Jan. 29, 2024, and was later pronounced dead, the outlets reported.

Originally, the jury in Sheffield was told there was no physical explanation for Mia’s psychosis.

On Monday, however, pathologist Marta Cohen testified that new blood test results were “conclusive,” confirming that Mia had autoimmune encephalitis, the BBC reported.

AE can be life-threatening and can cause a wide range of symptoms, including psychiatric changes, according to the Mayo Clinic.

After the test results were revealed in court, Mia’s mother, Chloe Hayes, and other relatives were seen wiping away tears, the BBC reported.

The family’s ordeal began on Dec. 31, 2023, when Mia tried to get knives from the kitchen and her mother struggled to stop her, YorkshireLive reported.

During the hearing, the court was told that Mia was hallucinating and hearing voices that said she needed to go to heaven or something terrible would happen to her loved ones.

Fearing for her safety, the family took her to Queen’s Medical Centre in Nottingham on New Year’s Eve. By Jan. 9, 2024, she was transferred to the Becton Centre after doctors concluded there was no physical cause for her psychosis, according to YorkshireLive.

Even though staff were monitoring her with hourly night checks, Mia was found unresponsive on Jan. 29 and died the following day, the BBC reported.

Cohen told the court that the cause of death remained “compression of the neck,” but said it was the result of “acute psychosis” brought on by the newly confirmed autoimmune condition, according to the outlet.

Pediatric neurologist Dr. Mike Taylor, who appeared as an expert earlier on Monday, initially told the court it was “possible” but not “probable” that Mia had AE. After seeing the blood test results, he later testified that it was now “definite” that she had the condition, the BBC reported.

While giving evidence, Taylor also said it was “quite concerning” that doctors at Queen’s Medical Centre had allegedly not carried out more tests, though he acknowledged the difficulties clinicians face in diagnosing such a complex condition.

Treatments for AE can themselves carry serious risks, including death, Taylor told the court, according to the BBC. He described the illness as a “complex and rare presentation which is very difficult for clinicians to pick up,” ITV reported, adding that extreme psychosis is exceptionally rare in 12-year-old children.

The final day of the inquest is scheduled for Friday, Nov. 28, according to the Sheffield City Council website.

Sheffield Coroner’s Court did not immediately respond to a request for comment.

As the investigation continues, Mia’s family is focused on remembering who she was beyond her illness. Hayes told the court that her daughter loved drawing, singing and horseback riding, ITV reported. When she grew up, Mia hoped to become either a beauty salon owner or a veterinarian.