April 18, 2022
People with mental health conditions, including substance use disorders, are at higher risk for breakthrough COVID-19 infections, even when fully vaccinated, new research suggests.
A study found participants with mental health illnesses were 3% more likely to have a breakthrough case in 2021. Seniors had the highest risk, even when accounting for other factors that affect COVID-19, including obesity, diabetes, heart disease and cancer.
Seniors with psychiatric conditions were up to 24% more likely to have a breakthrough case. For younger adults with these conditions, the risk was up to 11% higher.
The risk of breakthrough COVID was 24% higher for seniors with substance use disorders, and 23% higher for seniors with psychotic disorders. It was 16% higher for those with bipolar disorder, 14% higher those with adjustment disorder and 12% higher for those with anxiety.
For younger adults, those with substance use disorders were 11% more likely to have a breakthrough case. Adjustment disorder increased the risk by 9%. Adjustment disorders are extreme emotional reactions to stressful events or life changes.
Psychotic disorders that cause delusions and hallucinations were the only group of mental health disorders not associated with an increased rate of breakthrough infections, researchers found.
The study wasn't designed to prove causal link between these mental health conditions and breakthrough infections, but they have theories about why this happens.
"Our research suggests that increased breakthrough infections in people with psychiatric disorders cannot be entirely explained by socio-demographic factors or pre-existing conditions," said researcher Aoife O’Donovan, of the University of California, San Francisco and the San Francisco Veterans Affairs Health Care System.
"It's possible that immunity following vaccination wanes more quickly or more strongly for people with psychiatric disorders and/or they could have less protection to newer variants."
The higher incidence of breakthrough infection among seniors may be due to "decreased immunological response to vaccine that has been associated with some psychiatric disorders, which may be more substantial in older adults," researcher Kristen Nishimi, of UCSF, added.
Older adults with psychiatric disorders also "may require more frequent in-person care, which could increase their interactions with the health care system," she said.
The researchers also noted that people with mental health issues may be more likely to engage in risky behaviors or be in situations with higher risk of COVID-19 transmission.
"More preventative measures like booster vaccinations or increased SARS-CoV-2 screening could be considered for these individuals," Nishimi told U.S. News & World Report.
Previous research backs up these theories. Major depression has been proven to cause inflammation in the brain and the body, which weakens the immune system.
Other studies have shown that people with a history of mental illness are more likely to develop and die from COVID-19 than people without it. The role of the immune system in psychiatric disease, however, remains understudied.
The UCSF study included more than 263,000 patients of the U.S. Department of Veterans Affairs. The study participants average age was 66 and most of them were male. They were all fully vaccinated and had at least one COVID-19 test.
A little more than half of the study participants had been diagnosed with a psychiatric disorder and 14.8% of them developed a breakthrough COVID-19 infection, which was confirmed by a positive COVID-19 test.