The study’s findings were a mix of good and bad news, said Paul Harrison, a professor of psychiatry at the University of Oxford and the study’s senior author. Among the reassuring aspects was the rapid resolution of symptoms such as depression and anxiety.
“I was surprised and relieved at how quickly the psychiatric sequelae subsided,” Harrison said.
David Putrino, director of rehabilitation innovation at Mount Sinai Health System in New York, who has been studying the lasting effects of the coronavirus since the start of the pandemic, said the study revealed some very troubling results.
“This allows us to see the emergence of significant neuropsychiatric sequelae in people with unequivocally Covid and more often 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 emphasized that it was not strictly long-term Covid research.
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“It would be presumptuous and unscientific to immediately assume that everyone [study] The cohort had a long period of covid,” Putrino said. But the study, he said, “informs long-covid research.”
Between 7 million and 23 million in the United States, according to the latest government estimates, have prolonged covid — 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 subsides. Those numbers are expected to rise as the coronavirus settles in as an endemic disease.
The study was led by Oxford University Senior Research Fellow Maxime Tacquet, who specializes in using big data to shed light on psychiatric disorders.
The researchers matched nearly 1.3 million patients diagnosed with COVID-19 between January 20, 2020 and April 13, 2022, with an equal number of patients with other respiratory illnesses during the pandemic. The data, provided by the electronic health record network TriNetX, came largely from the United States but also included data from Australia, the UK, Spain, Bulgaria, India, Malaysia and Taiwan.
The study group, which included 185,000 children and 242,000 older adults, found that risks varied by age, with people 65 and older having the greatest risk of permanent neuropsychiatric effects.
For people between the ages of 18 and 64, a particularly significant increased risk was persistent brain fog, which affected 6.4 percent of people with Covid compared to 5.5 percent in the control group.
Six months after infection, the children were not found to be at increased risk of mood disorders, although they remained at greater risk of brain fog, insomnia, stroke and epilepsy. None of those effects were permanent for the children. With epilepsy, which is extremely rare, the increased risk was greater.
The study found that 4.5 percent of elderly people developed dementia in the two years after infection, compared with 3.3 percent of the control group. That 1.2-point increase in diagnoses as damaging as dementia is particularly worrisome, the researchers said.
The study’s reliance on troves of de-identified electronic health data raised some concerns, especially considering the tumultuous timing of the pandemic. Long-term outcomes can be difficult to track when patients may have sought care through different health systems, including some outside the TriNetX network.
“I personally find it impossible to judge the validity or conclusions of data when the source of the data is shrouded in mystery and the sources of the data are kept confidential by legal agreement,” said Harlan Krumholz, a Yale scientist who develops online. A platform where patients can enter their own health data.
Taquet said the researchers used several means to evaluate the data, including whether it reflected what was already known about the epidemic, such as the decline in death rates during the Omicron wave.
Also, Taquet said, “The validity of the data is no better than the validity of the diagnosis. If clinicians make mistakes, we will make the same mistakes.
The study follows previous research by the same group, which reported last year that a third of Covid patients experienced a mood disorder, stroke or dementia six months after infection.
While cautioning that it is impossible to make a complete comparison between the effects of recent variants, including Omicron and its subvariants, which are currently driving the infection, and those that were prevalent a year or more ago, the researchers noted some preliminary findings: Although Omicron. Because of the less severe immediate symptoms, long-term neurological and psychiatric consequences appeared like delta waves, indicating that the burden on the world’s health-care systems may persist even in less-severe variants.
Hannah Davis, co-founder of the Patient-Led Research Collaborative, which studies chronic Covid, said the finding was meaningful. “This goes against the myth that Omicron is more mild for long-term covid, which is not based on science,” Davis said.
“We see it all the time,” Putrino said. “Normal conversation leaves out the long covid. The severity of the initial infection doesn’t matter when we talk about the long-term consequences that ruin people’s lives.”
Dan Keating contributed to this report.