People infected with COVID-19 infection can be more at risk of psychosis, dementia, seizures and brain fog for up to two years compared to other respiratory infections, finds a study published in The Lancet Psychiatry on August 18.

The study led by researchers at the University of Oxford, UK, however, showed that the increased risks of depression and anxiety after COVID-19 are short-lived and there is no overall excess of cases.

"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. 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," said Professor Paul Harrison, from the varsity's Department of Psychiatry.

The findings, based on neurological and psychiatric diagnoses in over 1.25 million people following diagnosed COVID-19 infection, reported on 14 neurological and psychiatric diagnoses over a 2-year period and compared their frequency with a matched group of people recovering from other respiratory infections. It also reported data in children and older adults separately, and compared data across three waves of the pandemic.

Results in children (under 18) showed similarities and differences to adults. The likelihood of most diagnoses after COVID-19 was lower than in adults, and they were not at greater risk of anxiety or depression than children who had other respiratory infections. However, like adults, children recovering from COVID-19 were more likely to be diagnosed with some conditions, including seizures and psychotic disorders.

More neurological and psychiatric disorders were seen during the delta variant wave than with the alpha variant. The omicron variant, although less severe in acute illness, is associated with similar neurological and psychiatric risks as delta.

The study also noted several limitations. It is not known how severe, or how long-lasting, the disorders are. Nor is it clear when they began, since problems may be present for some time before a diagnosis is made. Unrecorded cases of COVID-19 and unrecorded vaccinations introduce some uncertainty into the results, the researchers said.