The researchers who conducted the analysis said it was not clear how the virus was linked to psychiatric conditions such as anxiety and depression, but that these were the most common diagnoses among the 14 disorders that were considered.
Stroke, dementia and other neurological disorders after Covid-19 are more rare, according to the researchers, but they are still significant, especially in patients who have had severe illness.
“Our results indicate that brain diseases and psychiatric disorders are more common after Covid-19 than after influenza or other respiratory infections,” said Max Taquet, a psychiatrist at the British University of Oxford, one of the co-authors of the work.
The study was unable to determine the biological or psychological mechanisms involved, Taquet said, but urgent research is needed to identify them “with a vision to prevent and treat them”.
Health experts are increasingly concerned about evidence of higher risks of neurological and mental disorders among Covid-19 survivors. A previous study by the same researchers concluded last year that 20% of Covid-19 survivors were diagnosed with a psychiatric problem within a three-month period.
The new study, published in the journal Lancet Psychiatry, analyzed the health records of 236,379 Covid-19 patients, most of them in the United States, and found that 34% of them were diagnosed with psychiatric or neurological illnesses within six months.
The disorders are significantly more common in Covid-19 patients than in comparison groups with people who recovered from flu or other respiratory infections in the same amount of time, the scientists said, suggesting that Covid-19 has a specific impact .
Anxiety, with 17%, and mood disorders, with 14%, are the most common, and do not seem to be related to how mild or severe the patient’s Covid-19 infection was.
Among those admitted to intensive care units with severe Covid-19, however, 7% had a stroke within six months, and about 2% were diagnosed with dementia.
“Although the individual risks for most disorders were small, the effect across the population can be substantial,” said Paul Harrison, professor of psychiatry at Oxford who led the study.
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