By Kelli Whitlock Burton
Schizophrenia and severe mood and anxiety disorders are associated with a significantly lower risk of contracting COVID-19, but are linked to a two-to-four-fold increased risk of death from the virus, new research shows.
The study results held true after controlling for other risk factors and contradict a previous study that showed no increased risk of mortality associated with mood or anxiety disorders. The findings come as the total number of deaths in the U.S. approaches 800,000.
"These patients were less likely to become infected because they were probably less exposed, but once they have the infection, they are more likely to have worse outcomes," lead author Antonio L. Teixeira, MD, PhD, professor of psychiatry at McGovern Medical School at The University of Texas Health Science Center at Houston, told Medscape Medical News .
The study was published online on November 23 in JAMA Network Open .
Unexpected discovery
Researchers analyzed the electronic medical records of 2.5 million adults with private health insurance who underwent COVID-19 testing in 2020.
The overall positivity rate for the entire cohort was 11.91%, and patients with severe psychiatric illnesses had a positivity rate below that. Positivity rates were 9.86% for individuals with schizophrenia or mood disorders and 11.17% for those with anxiety disorders.
Despite their lower positivity rate, patients with schizophrenia had the highest probability of death from COVID-19 after adjusting for age, race, body mass index and comorbidities (ORa, 3.74; 95% CI, 2.66 – 5.24).
Those results weren't very surprising, Teixeira said, since previous studies had reported similar findings. However, the data on people with mood and anxiety disorders were unexpected.
Patients with mood disorders were almost three times more likely to die (aOR, 2.76; 95% CI, 2.00 – 3.81), and those with anxiety disorders had more than twice the risk of mortality (aOR, 2.34; 95% CI, 1.68 – 3.27).
“We expected some increase, but there was also strong evidence in those populations,” he said. “We were particularly surprised by the data on patients with anxiety disorders.”
An outstanding question
These findings contradict a January 2021 study that showed no significant increase in mortality risk among people with mood or anxiety disorders.
The methodology and timing of the study could explain some of the differences, Katlyn Nemani, MD, assistant professor of psychiatry research at NYU Grossman School of Medicine, who led that earlier study, told Medscape Medical News .
Nemani's study had a smaller sample size, examined mortality over a 30-day period after a positive COVID-19 test, and was limited to the peak of the pandemic in New York, between March and May 2020. Teixeira's team examined a full year of data and assessed mortality for 7 days after a positive test.
"It is possible that patients with some psychiatric disorders were less likely to receive or respond successfully to treatment for severe COVID-19 that evolved during the course of the pandemic," Nemani said, adding that it is also possible that the differences in mortality in the days following the infection lessened over time.
While a meta-analysis published in July and reported by Medscape Medical News at the time showed higher COVID-19 mortality among patients with mood disorders, the risk was much lower than that reported in this new study. That report, which included 33 studies in 22 countries, also found no increased risk among people with anxiety disorders.
In October, the Centers for Disease Control and Prevention added mood disorders to the list of medical conditions that increase the risk of more severe COVID-19. Schizophrenia was already on that list.
“The remaining question is what underlies this increased risk,” Nemani said. “Future studies focusing on immune-mediated mechanisms and other potential explanations will help guide targeted interventions to reduce morbidity and mortality in this vulnerable population.” JAMA Netw Open . Published online November 23, 2021.