A study published this week in the Lancet Psychiatry showed increased risks of certain brain disorders two years after infection with the coronavirus, shedding new light on the long-term neurological and psychiatric aspects of the virus.
The analysis, conducted by researchers at the University of Oxford and drawing on data from the health records of more than one million people worldwide, found that while the risks of many common psychiatric disorders are back to normal within months, people remained at an increased risk of dementia, epilepsy, psychosis, and cognitive impairment (or brain fog) two years after contracting covid. Adults seemed to be at particular risk of long-lasting brain fog, a common complaint among coronavirus survivors.
The study was a mix of good news and bad news, said Paul Harrison, professor of psychiatry at the University of Oxford and lead author of the study. Among the reassuring aspects was the rapid resolution of symptoms such as depression and anxiety.
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“I was surprised and relieved by how quickly the psychiatric sequelae subsided,” Harrison said.
David Putrino, director of rehabilitation innovation at Mount Sinai Health System in New York, which has studied the lasting impacts of the coronavirus since the start of the pandemic, said the study revealed some very disturbing results.
“This allows us to definitely see the emergence of significant neuropsychiatric sequelae in individuals who have had covid and much more frequently than those who do not,” he said.
Because it focused only on the neurological and psychiatric effects of the coronavirus, the study authors and others stressed that it was not strictly long-term research.
“It would be overstated and unscientific to immediately assume that everyone in the [study] cohort had long covid,” Putrino said. But the study, he said, “sheds light on long covid research.”
Between 7 and 23 million people in the United States have long been suffering from covid, according to recent government estimates – a catch-all term for a wide range of symptoms including fatigue, shortness of breath and anxiety, that persist for weeks and months after the acute infection resolves. These numbers are expected to increase as the coronavirus takes hold as an endemic disease.
The study was led by Maxime Taquet, a senior researcher at the University of Oxford who specializes in using big data to shed light on psychiatric disorders.
The researchers matched nearly 1.3 million patients with a diagnosis of covid-19 between January 20, 2020 and April 13, 2022, with an equal number of patients who had other respiratory illnesses during the pandemic. The data, provided by electronic health record network TriNetX, came largely from the United States, but also included data from Australia, Britain, Spain, Bulgaria, India, Malaysia and Taiwan.
The study group, which included 185,000 children and 242,000 elderly people, found that the risks differed across age groups, with people aged 65 and over being most at risk for long-lasting neuropsychiatric affects.
For people aged 18 to 64, a particularly large increased risk was persistent brain fog, affecting 6.4% of people who had had covid compared to 5.5% in the control group.
Six months after infection, the children were not at increased risk for mood disorders, although they remained at increased risk for brain fog, insomnia, stroke and epilepsy. None of these effects were permanent for the children. With epilepsy, which is extremely rare, the increased risk was greater.
The study found that 4.5% of older people developed dementia within two years of infection, compared to 3.3% of the control group. This 1.2 point increase in such a damaging diagnosis as dementia is particularly concerning, the researchers said.
The study’s reliance on a wealth of anonymized electronic health data prompted some caveats, especially during the tumultuous times of the pandemic. Tracking long-term outcomes can be difficult when patients may have sought care through many different healthcare systems, including some outside of the TriNetX network.
“I personally find it impossible to judge the validity of data or conclusions when the source of the data is shrouded in mystery and the sources of the data are kept secret by legal agreement,” said Harlan Krumholz, a Yale scientist who developed an online website. platform where patients can enter their own health data.
Taquet said the researchers used several ways to assess the data, including making sure it reflected what was already known about the pandemic, such as the drop in death rates during the omicron wave.
Moreover, Taquet said, “the validity of the data will not be better than the validity of the diagnosis. If clinicians make mistakes, we will make the same mistakes.”
The study follows previous research from the same group, which reported last year that a third of covid patients suffered from mood disorders, strokes or dementia six months after infection with the virus. coronavirus.
While cautioning that it is impossible to make comprehensive comparisons between the effects of recent variants, including omicron and its subvariants, which are currently causing infections, and those prevalent a year or more, the researchers presented some initial results: Although omicron caused less severe immediate symptoms, the longer-term neurological and psychiatric outcomes appeared similar to delta waves, indicating that the burden on global health systems could continue even with less severe variants.
Hannah Davis, co-founder of the Patient-Led Research Collaborative, which has long studied covid, said the finding was significant. “It goes against the narrative that omicron is softer for a long time, which is not based on science,” Davis said.
“We see this all the time,” Putrino said. “The general conversation leaves out the long covid. The severity of the initial infection doesn’t matter when we’re talking about long-term sequelae that ruin people’s lives.”
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Dan Keating of The Washington Post contributed to this report.
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