The Bronfenbrenner Center for Translational Research

• A new systematic review finds that COVID infections increase the risk of mental health disorders.
• Women, people with lower incomes, and those with more severe infections are at greater risk.
• Scientists are still trying to understand the biological mechanisms at play.

More than four years after the first humans became infected with the SARS-CoV-2 virus, scientists understand more than ever before about how COVID-19 affects people. Beyond respiratory symptoms, COVID can lead to nausea, vomiting, diarrhea, rashes, and even eye infections. We’ve also learned that people can experience long COVID, which involves continued symptoms for months or even years after they initially get sick.

Now, new data is shedding light on how COVID affects mental health. A systematic review published this month in the journal BMC Psychiatry takes a careful look at the long-term mental health effects of COVID-19. In the analysis, Iranian public health researchers pooled the data from hundreds of studies that used validated assessment tools for depression, anxiety, and sleep disorders to quantify mental health disorders among patients with long COVID.

“Initially, research was centered on analyzing the psychosocial reaction to the COVID pandemic and the effects of various preventive measures, including lockdowns, school closures, and travel restrictions, on the mental health outcomes of the general population,” they wrote. “However, recent studies have expanded this scope to include not only the effects of pandemic-related circumstances but also the impact of COVID-19 as a debilitating disease.”

To look at depression rates, the researchers combined the data from 143 studies with more than 7.7 million participants with long COVID. They found that 23 percent of participants experienced depression, compared with approximately 4 percent of the general population at any given time.

For anxiety, researchers combined the data from 132 studies with more than 9.3 million participants with long COVID and found 23 percent reported symptoms of anxiety. Comparatively, about 4 percent of the general population experiences an anxiety disorder at any given time.

To quantify sleep problems, the researchers combined data from 27 studies with more than 15,000 participants and found 45 percent of patients with long COVID experienced sleep problems, compared with approximately 15 percent of the general population who report trouble sleeping at any given time.

Clearly, people with long COVID are significantly more likely to experience mental health problems. Researchers stressed the study’s focus on the mental health status of people infected with COVID, not how the experience of living through a global pandemic affected the mental health of the broader society.

The analysis was also able to identify risk factors for developing mental health disorders as part of a COVID infection. Older people, women, people with lower socioeconomic status, and people with pre-existing mental health conditions were all more likely to develop mental health disorders when they were infected with COVID. In addition, people with more severe initial infections were at a greater risk of developing mental health problems months later.

What’s going on here? Medical experts don’t yet fully understand how COVID affects mental health. There is some evidence that the virus invades the central nervous system and damages neurons. Another theory is that COVID causes problems with blood vessels and blood flow, causing indirect harm to the brain. In addition, COIVD causes an inflammatory response in the body that can disrupt neurotransmitter activity and lead to oxidative stress in the cells, which aggravates mental health symptoms.

The take-home message: A large and growing body of evidence demonstrates people infected with COVID are significantly more likely to experience mental health problems compared to the general population.