Aug. 20, 2022 -- People who got COVID have a higher risk of developing brain disorders such as dementia, psychosis, and brain fog two years after they were infected than people who had other respiratory illnesses, a study published in The Lancet  has found.

University of Oxford researchers examined medical data on about 1.3 million people diagnosed with COVID from Jan. 20, 2020, and April 13, 2022, and compared it to data from an equal number of people who had other respiratory diseases. Most of the patients were from the United States.

Researchers said it was encouraging that the risk of anxiety and depression was “transient” for COVID patients, with the risk dropping sharply two months after infection.

By contrast, a higher risk of neurological and mental health conditions such as dementia, brain fog, and epilepsy or seizures remained at the end of the two-year study period.

“The findings shed new light on the longer-term mental and brain health consequences for people following COVID-19 infection,” Max Taquet, MD, who led the analysis, said in a University of Oxford news release.

“The results have implications for patients and health services and highlight the need for more research to understand why this happens after COVID-19, and what can be done to prevent these disorders from occurring or treat them when they do.”

Overall, brain fog, also known as cognitive deficit, was a persistent problem over the long term.

Among people aged 18-64 who got COVID, 6.4% (640 out of 10,000 people) reported brain fog after two years, compared to 5.5% of the control group, according to The Guardian.

Among people 65 and older, 15.4% developed brain fog and 4.5% developed dementia after two years, compared to 12.3% and 3.3% of the control group, respectively, who reported those diagnoses.

Records showed children who got COVID overall had fewer of the follow-up problems being studied than did adults, though after two years they still had a higher incidence of conditions such as seizures than children in the control group.

The study found no great difference between the Delta and Omicron waves in the risk of post-infection problems.

“It is good news that the excess of depression and anxiety diagnoses after COVID-19 is short-lived, and that it is not observed in children,” study leader Paul Harrison of the University of Oxford Department of Psychiatry said in the news release.

“However, it is worrying that some other disorders, such as dementia and seizures, continue to be more likely diagnosed after COVID-19, even two years later. It also appears that omicron, although less severe in the acute illness, is followed by comparable rates of these diagnoses.”

Show Sources

The Lancet. “Neurological and psychiatric risk trajectories after SARS-CoV-2 infection: an analysis of 2-year retrospective cohort studies including 1 284 437 patients”

The University of Oxford. “Increased risk of some neurological and psychiatric disorders remains two years after COVID-19 infection”

The Guardian. “Covid linked to longer-term elevated risk of brain fog and dementia”

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