Six months after developing COVID-19, one out of every three patients has been diagnosed with a mental or neurological disorder, according to a sweeping new study.

Researchers looked at the medical records of 230,000 U.S. survivors of COVID-19 and found 34% of them experienced such issues. Of those, 13% had no recorded history of a mental or psychological diagnosis.

“The data are worrying,” says Paul Harrison, professor of psychiatry at the University of Oxford and lead author of the study. “On the other hand, you could say, two-thirds of people after COVID are not getting any diagnosis of this kind. So, there’s some good news.”

The study, published Tuesday in the Lancet Psychiatry, was the largest of its kind. The most common problems found were anxiety and mood disorders, affecting 17% and 14% of people, respectively. A small but “non-trivial” percentage were diagnosed with neurological disorders like stroke, dementia or psychosis.

“As a psychiatrist, I think psychosis is a particularly interesting and important group, not to get lost between anxiety and mood disorders and stroke,” Harrison says.

Of the COVID-19 patients that needed to be admitted to an intensive care unit, one in 33 developed psychosis. The findings reflect a phenomena that doctors have been increasingly reporting: new onset psychotic symptoms surfacing weeks after infection.

For some survivors, the issues have reportedly lingered for months — making psychosis one of an untold number of long-haul coronavirus symptoms.

Sarah Lowe, a clinical psychologist at the Yale School of Public Health, says the findings were “very striking, although in some ways not surprising.”

Lowe, who was not involved in the study, researches the aftermath of disasters, such as hurricanes and epidemics. Anxiety and depression are not uncommon and they can be a result of the pressure and trauma people experience, she says.

COVID-19 patients “were facing the extreme stress of a life-threatening illness during a global pandemic from a virus we were just learning about,” she says. “These people were scared for their lives” and often separated from their families.

While the drivers of anxiety and mood disorders are largely understood, questions remain about what could be behind post-virus neurological problems.

Whereas patients with more severe COVID-19 symptoms were more likely to develop neurological disorders, Harrison says, the severity did not affect their likelihood of developing anxiety or mood disorders.

“That suggests to me that there is a more direct effect of either the virus or your body’s immune reaction to the virus,” he says.

While the study does much to highlight the potential mental health fallout of COVID-19, it may underestimate the number of people affected.

Anxiety and depression have also emerged in non-patients. The Kaiser Family Foundation found that about four in 10 of U.S. adults reported such symptoms during the pandemic, regardless of if they had COVID-19. Rates were higher among frontline workers and people without job security.

“The majority of people who have mental disorders also do not seek treatment,” Lowe says, so the full toll may be unknown.

Whatever the case, the results point to a potential flood of mental health needs as the pandemic drags on. Already, 57% of U.S. adults with a mental illness receive no treatment, according to the nonprofit Mental Health America. Five million are uninsured.

“Health services around the world need to be ready,” he says.

Dean Russell produced and edited this interview for broadcast with Tinku Ray. Russell also adapted it for the web.

This article was originally published on WBUR.org.

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