Mental illness raises the risk of Severe COVID-19. Why?

It’s been clear since the early days of the pandemic: People with mental illness are more likely to have severe outcomes from COVID. Compared with the general population, they’re at higher risk of being hospitalized, developing long COVID, or dying from an infection.

That fact puts mental illness on the same list as better-known COVID risk factors like cardiovascular issues, chronic kidney disease, and asthma.

When it comes to COVID risk, mental illness “shouldn’t be treated differently than you treat diabetes or heart disease or cancer,” said Dr. Ziyad Al-Aly, the chief of research and development at the Veterans Affairs St. Louis Healthcare System.

Scientists now have a better understanding of who is vulnerable. While research has linked a wide range of mental illnesses to worse COVID outcomes, experts generally believe that the risk is greatest for people with severe or unmanaged mental health conditions — suggesting that someone with schizophrenia, for example, is more likely to get sicker from COVID than someone receiving treatment for anxiety. They also have several hypotheses about why mental illness might make people more susceptible.

The Strain of Stress

Many mental health conditions can lead to chronically high-stress levels. Stress sabotages the immune system, flooding the body with hormones like cortisol and adrenaline. Those hormones make it harder to produce certain immune cells that are crucial for fighting off illnesses.

“The whole system is not designed to be constantly activated,” said Andrea Lynne Roberts, a researcher at Harvard University who has studied the effects of mental health conditions on COVID outcomes. That’s why people with mental illness may be more vulnerable to viral infections in general, from the common cold to COVID.

Elevated stress levels can also lead to persistently high blood pressure and more plaque deposits in the heart, contributing to cardiovascular disease — which is known to predispose people to more severe COVID infections.

Medication Effects

Some antipsychotic drugs might weaken the immune system, making it harder to mount a response to a threat like a virus, said Maxime Taquet, a psychiatry researcher at the University of Oxford.

Some antidepressant medications and antipsychotics can also lead to weight gain; for that and other reasons, obesity commonly occurs in people with some mental illnesses. Data from the Centers for Disease Control and Prevention shows that obesity is tied to an increased risk of hospitalization from a COVID-19 infection.

Dr. Thida Thant, an assistant professor of psychiatry at the University of Colorado School of Medicine, stressed that those concerns should not dissuade people from taking medications for their mental health because the benefits of treatment far outweigh these potential risks.

Inflammation in the Brain

A COVID-19 infection raises the risk that anyone will develop a mental illness, even with no history of psychiatric disorders. That’s partly because the virus “wreaks havoc in the brain,” causing inflammation in areas that control emotion and cognition, Al-Aly said.

For people who already have mental illness, COVID-19 can make things worse. In some patients, certain long COVID symptoms — depression, anxiety, fatigue, brain fog — might be signs that a COVID infection has exacerbated a preexisting mental illness, Thant said.

The Circumstances Around Mental Illness

Sometimes worse outcomes from COVID have less to do with the mental illnesses themselves and more with external factors that sometimes accompany them. For example, people with mental illness are more likely to smoke and therefore have worse lung health, said Nora Volkow, director of the National Institute on Drug Abuse and a co-author of a study that showed that people with mental health disorders were significantly more likely to die or be hospitalized due to COVID.

People with severe mental illnesses are also more likely to experience poverty and may not be able to afford health care. They may also struggle to get enough sleep, maintain a balanced diet and attend to other aspects of their health, Thant said.

And the stigma around mental illness can prevent people from seeking medical care, Volkow said, which can be particularly critical when it comes to COVID. Paxlovid, an antiviral drug that slashes the risk of hospitalization and death from the virus, needs to be taken within the first five days of symptoms, so getting a prescription early into the course of disease is essential.

But people with mental health conditions may not be able to access the care they need to get a prescription — or even know they qualify for the antiviral in the first place.

This article originally appeared in The New York Times.