People with Covid-19 continue to face increased risk of developing neurological and psychiatric conditions like psychosis, dementia and brain fog two years after infection, new research suggests.
There is also an increased risk of anxiety and depression in adults, but this subsides within two months of infection and, over two years, is no more likely than after other respiratory infections.
The study of some 1.25 million people diagnosed with coronavirus found that children were more likely to be diagnosed with some conditions, like seizures and psychotic disorders.
However, the likelihood of most diagnoses after Covid was lower than in adults.
According to the research, the delta variant was associated with more disorders than the alpha, and omicron was associated with similar neurological and psychiatric risks as delta.
The researchers are calling for more support and resources for healthcare providers in diagnosing and managing these conditions.
Professor Paul Harrison, lead author of the study, from the University of Oxford, said: “In addition to confirming previous findings that Covid-19 can increase the risk for some neurological and psychiatric conditions in the first six months after infection, this study suggests that some of these increased risks can last for at least two years.
“The results have important implications for patients and health services as it suggests new cases of neurological conditions linked to Covid-19 infection are likely to occur for a considerable time after the pandemic has subsided.
“Our work also highlights the need for more research to understand why this happens after Covid-19, and what can be done to prevent or treat these conditions.”
The study analysed data on 14 neurological and psychiatric diagnoses gathered from electronic health records mostly from the US over a two-year period.
It found that in adults, the risk of having a depression or anxiety diagnosis initially increased after infection.
But it returned to the same as with other respiratory infections after a relatively short time depression at 43 days, anxiety at 58 days.
After two years, there was no difference in the overall incidence of depression and anxiety between the Covid group and the other respiratory infections group.
However, the risk of diagnosis of some other neurological and mental health conditions was still higher after coronavirus than for other respiratory infections at the end of the two-year follow-up.
Adults aged 18-64 who had Covid up to two years previously had a higher risk of brain fog, and muscle disease, compared to those who had other respiratory infections up to two years previously.
The research also found that in adults aged 65 and over who had Covid up to two years previously, there was a higher occurrence of brain fog (1,540 cases per 10,000 people), dementia (450 cases per 10,000 people) and psychotic disorder (85 cases per 10,000 people) compared to those who previously had a different respiratory infection.
Prof Harrison said that while the numbers are not trivial, they are not huge and need to be set against the increasing burden of mental and brain health problems that may have occurred in the whole population because of the pandemic.