Large study looks at COVID-19 infection and subsequent mental health, neurological conditions

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One in three novel coronavirus (COVID-19) survivors received a neurological or psychiatric diagnosis within six months of infection with SARS-CoV-2, the virus that causes COVID-19, according to a new observational study published in the journal The Lancet Psychiatry.

Since the COVID-19 pandemic began, there has been growing concern that survivors might be at increased risk of neurological disorders. A previous observational study by the same research group reported that COVID-19 survivors are at increased risk of mood and anxiety disorders in the first three months after infection. However, there have been no large-scale data examining the risks of neurological as well as psychiatric diagnoses in the six months after COVID-19 infection.

For the current study, researchers analyzed data from the electronic health records of 236,379 COVID-19 patients from the United States-based TriNetX network, which includes more than 81 million people. Patients who were older than 10 years and who became infected with the SARS-CoV-2 virus after January 20, 2020, and were still alive on December 13, 2020, were included in the analysis. This group was compared with 105,579 patients diagnosed with influenza and 236,038 patients diagnosed with any respiratory tract infection, including influenza, according to the study.

Overall, the estimated incidence of being diagnosed with a neurological or mental health disorder following COVID-19 infection was 34 percent. For 13 percent of these people it was their first recorded neurological or psychiatric diagnosis, the researchers said.

The most common diagnoses after COVID-19 were anxiety disorders occurring in 17 percent of patients, mood disorders occurring in 14p percent, substance misuse disorders occurring in 7 percent, and insomnia occurring in 5 percent. The incidence of neurological outcomes was lower, including 0.6 percent for brain hemorrhage, 2.1 percent for ischemic stroke, and 0.7 percent for dementia.

Risks of a neurological or psychiatric diagnosis were greatest in, but not limited to, patients who had severe COVID-19. Compared to the overall 34 percent incidence, a neurological or psychiatric diagnosis occurred in 38 percent of those who had been admitted to hospital, 46 percent of those in intensive care, and 62 percent in those who had delirium or encephalopathy during their COVID-19 infection. This gradient of risk applied to individual disorders too, the researchers said.

For example, 2.7 percent of people needing intensive care and 3.6 percent of people with encephalopathy had a brain hemorrhage, compared to 0.3 percent in people without hospitalization; 6.9 percent and 9.4 percent had ischemic stroke, compared to 1.3 percent without hospitalization; 1.7 and 4.7% developed dementia, compared to 0.4 percent without hospitalization; and 2.8 percent and 7 percent were diagnosed with a psychotic disorder, compared to 0.9 percent without hospitalization, according to the study.

The authors also said they looked at people who experienced flu and other respiratory tract infections over the same time frame to help understand whether these neurological and mental health complications were linked specifically to COVID-19. After considering underlying health characteristics, such as age, sex, ethnicity, and existing health conditions, there was overall a 44 percent greater risk of neurological and mental health diagnoses after COVID-19 than after flu, and a 16 percent greater risk after COVID-19 than with respiratory tract infections.

As a result, the authors said that COVID-19 does lead to a greater risk of neurological and psychiatric disorders than these other health conditions. However, this was not seen for all conditions. For example, there was no clear evidence that COVID-19 led to an increased risk of parkinsonism or and Guillain-Barré syndrome.

The authors note several limitations to their study. Firstly, the completeness and accuracy of the electronic health records is not known. Secondly, many people with COVID-19 have mild or no symptoms and do not present for healthcare, therefore, the people studied here are likely to have been more severely affected than in the general population. Thirdly, the severity and course of the neurological and psychiatric disorders is not known.

"These are real-world data from a large number of patients,” said Paul Harrison, MA, BM. BCh, DM (Oxon), FRCPsych, lead author of the study and a professor of psychiatry at the University of Oxford, in a statement. “They confirm the high rates of psychiatric diagnoses after COVID-19 and show that serious disorders affecting the nervous system, such as stroke and dementia, occur too. While the latter are much rarer, they are significant, especially in those who had severe COVID-19."

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