COVID-19 vaccination programs are rolling out around the world. Meanwhile, scientists are still hard at work identifying the groups of people most at risk of contracting the infection or dying from it – people who more urgently need the long-awaited protection vaccines can provide.

Now, a new study of nearly 7,400 people in New York, who all tested positive for COVID-19, has found that the odds of people diagnosed with schizophrenia dying from COVID-19 are nearly three times higher than for those without the disorder.

It suggests there might be something about schizophrenia that makes these people more vulnerable to viral infections, though the startling findings may just be a reflection of healthcare inequalities exposed by the pandemic.

"Our findings illustrate that people with schizophrenia are extremely vulnerable to the effects of COVID-19," said psychiatrist Katlyn Nemani from New York University (NYU) Langone Medical Center.

"With this newfound understanding, health care providers can better prioritise vaccine distribution, testing, and medical care for this group," she added.

In the study, Nemani and her colleagues compared how people treated for COVID-19 in New York at the height of the region's coronavirus pandemic fared 45 days after testing positive.

Scouring medical records from the NYU Langone health system, which includes four hospitals, the team identified 7,350 adults who had tested positive for COVID-19 between March and May 2020, of which 75 had diagnosed schizophrenia.

Schizophrenia is a mental disorder that interferes with a person's perception of reality and affects their mood.

But it's worth noting here that schizophrenia is an enigmatic disease that scientists are still trying to understand, and this study only considered people with a documented history of the disorder.

The number of people with schizophrenia in the study was also not huge, though the overall sample size was broad and diverse. 

People with mood disorders such as anxiety also featured, but the analysis found these people had no increased risk of dying from COVID-19, even though previous studies have found individuals with mental conditions are more likely to get infected.

The odds of people with schizophrenia dying from COVID-19 were pretty grim: found to be 2.67 times more likely to die from coronavirus than people without schizophrenia.

The result means schizophrenia ranked as the second greatest risk factor (after age) for death by COVID-19 in this group of New Yorkers, after the study authors accounted for other variables, such as age, sex, race, diabetes, heart disease, and smoking (but not medication use or obesity).

"This is an alarming finding," said Tom Pollak, a psychiatrist at King's College London, who was not involved in the study.

"These patients are already amongst the most vulnerable members of society and are probably underserved by most healthcare systems worldwide." 

One possible explanation, proposed by the study authors, is that because schizophrenia disturbs the body's immune system – it's sent into overdrive by inflammatory cytokines – it could make these people more vulnerable to COVID-19 infections.

Yet some researchers who weren't involved in the study are making more cautious interpretations, saying that the observed disparity is more likely to be explained by lifestyle factors and comorbidities, such as obesity, common among people with schizophrenia.

Even without COVID-19, people with schizophrenia often have poor physical health, and it has long been known that this translates to a higher likelihood of dying early – as much as 20 years earlier than the average person, in some cases.

According to clinical psychiatrist David Owens from the University of Edinburgh, who was not involved in the research, the study "may, again, be illustrating the health and social inequalities to which patients with long-term psychiatric disorders such as schizophrenia remain prone".

Troubled by paranoia and barred by stigma, people with schizophrenia are often reclusive and may avoid seeking help.

But the study, by design, only looked at people who had access to COVID-19 testing and medical care – at a time when health services were greatly disrupted, and testing was restricted.

This could mean that the people in the study had a pretty severe case of COVID-19, or had family or friends who could help them get to hospital. Sadly, we cannot say what happened to anyone who perhaps had COVID-19 at home but did not seek medical care.

Even with the different takes on this study, if anything, it shows the need to focus our collective efforts on helping vulnerable people, like those with schizophrenia and other life-long health conditions.

"This [research] indicates it is vital that people with schizophrenia are seen as [a] high-risk group and have early access to vaccines," said psychiatrist and epidemiologist Matthew Hotopf, at King's College London, who wasn't involved with the study.

The research was published in the journal JAMA Psychiatry.

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