LONDON – A new study has delivered evidence that people who survive COVID-19 infection are at increased risk of being diagnosed with a psychiatric disorder, with almost one in five survivors getting a diagnosis of anxiety, depression or insomnia in the three months following a positive test for the virus.

Of these, one in four had not had a psychiatric disorder diagnosis before COVID-19.

In addition, people with a pre-existing psychiatric disorder were 65% more likely to be diagnosed with COVID-19, even when known risk factors such as diabetes, hypertension and obesity were taken into account.

“There are concerns that COVID-19 affects people’s mental health. This is the first robust study to show this is actually the case and to put some figures on this risk,” said Paul Harrison, professor of psychiatry at Oxford University, who led the research.

The study used Trinetx Analytics Network, a database that holds anonymized electronic health records of 69 million people in the U.S. who received health care from 54 providers. Among those, 62,354 had a diagnosis of COVID-19.

To assess the excess risk of mental health problems, the researchers compared the number of diagnoses of psychiatric disorders to those in patients with six other health conditions: influenza, respiratory tract infections, skin infections, gall stones, kidney stones and major fractures of the leg, pelvis or arm, between Jan. 20 to Aug. 1, 2020.

The study, published in Lancet Psychiatry, showed that while there was an increased incidence of psychiatric disorders in those six groups, the risk of getting a psychiatric disorder diagnosis in the 90 days post-COVID-19 infection was double that seen for any of the other health events.

If detecting an association between COVID-19 and a subsequent psychiatric disorder diagnosis was not that unexpected, the finding that those with a pre-existing psychiatric disorder were more likely to contract the virus was. “In people with none of the risk factors established for COVID-19, if they had a psychiatric diagnosis, they were at higher risk of getting COVID-19,” said Max Taquet, clinical fellow at the National Institute of Health Research (NIHR) at Oxford University, who conducted the statistical analysis.

“[This] needs investigation. In the meantime, psychiatric disorders should be added to the list of risk factors for COVID-19,” Taquet said.

Although the link between pre-existing psychiatric problems and COVID-19 infection was independent of the known physical health risk factors, the nature of the data on which the analysis was based meant confounding socioeconomic factors could not be excluded.

“At this point, interpretation is difficult,” said Harrison. It is possible something about the biology of psychiatric illnesses, or the drugs people are taking, predisposes them. There also could be socioeconomic, other behaviors, or general aspects of physical health not recorded in medical records. “It’s not implausible COVID-19 might have a direct effect on the brain possibly, but it needs to be studied,” he said.

Long COVID

Another NIHR study, Phosp-Covid, is recruiting 10,000 COVID-19 patients in an 18-month prospective study in the U.K., looking at all aspects of what has been labeled “Long COVID.”

John Geddes, head of the department of psychiatry at Oxford University, who is leading the work the project is doing on neurological consequences, said the main concerns are around: what impact COVID-19’s known effects on vasculature have on the brain; whether the immune response to the virus affects the brain; and the possibility of a direct effect of the virus on cells in the nervous system.

A small study of recovered patients in which Geddes was involved has reported the occurrence of tissue changes compared to controls in MRI brain scans. “The virus has effects across the body, but all mental and neurological symptoms are produced in the brain,” Geddes said.

The researchers suggest that the traumatizing effect of living through a pandemic could have mental health consequences even in those who do not contract the infection. They also consider the number of people getting psychiatric disorders post-COVID-19 is an underestimate, since it only relates to patients who have tested positive and who subsequently present with mental health problems.

In addition to anxiety, depression and insomnia, the study also identified that more cases of dementia had been diagnosed in the 90 days after a positive COVID-19 test. Harrison suggested this is likely to be a result of pre-existing dementia coming to light. “It may be, it was just brought to attention in people who had not been seen [by a doctor] for some time,” he said. “Dementia is not reversible, so we have to be particularly careful in not over-interpreting.”

Editor’s note: This story has been corrected to clarify that psychiatric diagnoses post COVID-19 related to both those with a previous history of anxiety, depression and insomnia and those being diagnosed with one of these conditions for the first time.