June 2, 2023 — Anxiety, depression, and COVID-19 can be a bad combination for your brain — and your long-term health.
Having anxiety and depression before a COVID infection increases the risk of developing long COVID, researchers have found.
Those with long COVID who develop anxiety and depression after an infection may have brain shrinkage in areas that regulate memory, emotion, and other functions as well as disruption of brain connectivity.
While many questions remain about these intertwined relationships, the associations aren’t a complete surprise. Experts already know that depression and anxiety are associated with inflammation and immune dysfunction, perhaps helping to explain the link between these mental health conditions, the risk of long COVID, and the changes in the brain.
Brain changes accompanying a COVID infection have concerned researchers since earlier in the pandemic, when U.K. Biobank researchers found brain atrophy, loss of grey matter, and decline in cognition in those infected with COVID compared with those not infected.
The ramifications of the research linking anxiety, depression and long COVID are far-reaching. According to the CDC, 12.5% of U.S. adults have regular feelings of anxiety (as well as nervousness and worry), and the latest Gallup Poll found that nearly 18% of adults currently have or are being treated for depression.
As of May 8, 10% of U.S. infected adults have long COVID, according to the CDC, and among U.S. adults ever infected, 27% have reported long COVID. Long COVID has been defined by the CDC as symptoms such as fatigue, brain fog, and cough that persist longer than 4 weeks and by the World Health Organization as symptoms persisting for 3 months or more.
Here’s a roundup of what the research shows about mental health and long COVID risk — along with other research finding that paying attention to health habits may reduce that risk.
Pre-Existing Depression, Anxiety, and Long COVID Risk
A history of mental health issues — including depression, anxiety, worry, perceived stress, and loneliness — raises the risk of long COVID if infection occurs, Harvard researchers have found.
The researchers evaluated data from three large, ongoing studies including nearly 55,000 participants to determine the effects of high levels of psychological distress before a COVID infection.
“Our study was purely survey based,” said Siwen Wang, MD, the study’s lead author and a research fellow at Harvard’s T.H. Chan School of Public Health at Harvard University.
At the start of the survey in April 2020, none of the participants reported a current or previous COVID infection. They answered surveys about psychological distress at the start of the study, at 6 monthly time points, then quarterly until November 2021.
Over the follow up, 3,193 people reported a positive COVID test and 43% of those, or 1,403, developed long COVID. That number may seem high, but 38% of the 55,000 were active health care workers. On the final questionnaire, they reported whether their symptoms persisted for 4 weeks or longer and thus had long COVID by the standard CDC definition.
Wang’s team then looked at the infected participants’ psychological status. Anxiety raised the risk of long COVID by 42%, depression by 32%, worry about COVID by 37%, perceived stress, 46%, and loneliness, 32%.
COVID patients with a history of depression or anxiety are also more likely than others to report trouble with cognition in the weeks after a COVID infection and to develop brain fog and long COVID, UCLA researchers found. They evaluated 766 people with a confirmed COVID infection; 36% said their thinking was affected within 4 weeks of the infection. Those with anxiety and depression were more likely to report those difficulties.
Long COVID, Then Anxiety, Depression, Brain Changes
Even mild cases of COVID infection can lead to long COVID and brain changes in those who suffer anxiety or depression after the infection, according to Clarissa Yasuda, MD, PhD, assistant professor of neurology at the University of Campinas in Sao Paulo, Brazil. She has researched long COVID’s effects on the brain, even as she is coping with being a long COVID patient.
In one of her studies, presented at the 2023 American Academy of Neurology meeting in April, she found brain changes in people with anxiety, depression, and COVID but not in those infected who did not have either mental health issue. She evaluated 254 people, median age 41, after about 82 days from their positive PCR test for COVID. Everyone completed a standard questionnaire for depression (the Beck Depression Inventory) and another for anxiety (the Beck Anxiety Inventory). She further divided them into two groups — the 102 with symptoms and the 152 who had no symptoms of either depression or anxiety.
Brain scans showed those with COVID who also had anxiety and depression had shrinkage in the limbic area of the brain (which helps process emotion and memory), while those infected who didn’t have anxiety or depression did not. The researchers then scanned the brains of 148 healthy people without COVID and found no shrinkage.
The atrophy, Yasuda said, “is not something you can see with your eyes. It was only detected with computer analysis. Visualization on an MRI is normal.”
The number of people in this study with mental health issues was surprisingly high, Yasuda said. “It was intriguing for us that we noticed many individuals have both symptoms, anxiety and depression. We were not expecting it at that proportion.”
The researchers found a pattern of change not only in brain structure but in brain communication. They found those changes by using specialized software to analyze brain networks in some of the participants. Those with anxiety and depression had widespread functional changes in each of 12 networks tested. The participants without mental health symptoms showed changes in just 5 networks. These changes are enough to lead to problems with thinking skills and memory, Yasuda said.
Explaining the Links
Several ideas have been proposed to explain the link between psychological distress and long COVID risk, Wang said. “The first and most mainstream mechanism for long COVID is chronic inflammation and immune dysregulation,” she said. “Several mental health conditions, such as anxiety and depression, are associated with inflammation and dysfunction and that might be the link between depression, anxiety, and long COVID.”
Another less mainstream hypothesis, she said, is that “those with long COVID have more autoantibodies and they are more likely to have blood clotting issues. These have also been found in people with anxiety, depression, or other psychological distress.”
Other researchers are looking more broadly at how COVID infections affect the brain. When German researchers evaluated the brain and other body parts of 20 patients who died from non-COVID causes but had documented COVID infections, they found that 12 had accumulations of the SARS-CoV-2 spike protein in the brain tissue as well as the skull and meninges, the membranes that line the skull and spinal cord. Healthy controls did not.
The findings suggest the persistence of the spike protein may contribute to the long-term neurological symptoms of long COVID and may also lead to understanding of the molecular mechanisms as well as therapies for long COVID, the researchers said in their preprint report, which has not yet been peer-reviewed.
In another recent study, researchers from Hamburg, Germany, performed neuroimaging and neuropsychological assessments of 223 people who were not vaccinated and recovered from mild to moderate COVID infections, comparing them to 223 matched healthy controls who had the same testing. In those infected, they found alterations in the cerebral white matter but no worse cognitive function in the first year after recovering. They conclude that the infection triggers a prolonged neuroinflammatory response.
Can the brain changes reverse? “We don’t have an answer right now, but we are working on that,” Yasuda said. For now, she speculates about the return of brain volume: “I think for most it will. But I think we need to treat the symptoms. We can’t disregard the symptoms of long COVID. People are suffering a lot, and this suffering is causing some brain damage.”
Lifestyle Habits and Risk of Long COVID
Meanwhile, healthy lifestyle habits in those infected can reduce the risk of long COVID, research by Wang and her colleagues found. They followed nearly 2,000 women with a positive COVID test over 19 months. Of these, 44%, or 871, developed long COVID. Compared with women who followed none of the healthy lifestyle habits evaluated, those with five to six of the habits had a 49% lower risk of long COVID.
The habits included: a healthy BMI (18.5 to 24.9), never smoking, at least 150 minutes weekly of moderate to vigorous physical activity, moderate alcohol intake (5-15 grams a day), high diet quality, and good sleep (7-9 hours nightly).
Yasuda hopes that mental health care — of those infected and those not — will be taken more seriously. In her commentary on her own long COVID experience, she wrote, in part: “I fear for the numerous survivors of COVID-19 who do not have access to medical attention for their post-COVID symptoms. … The mental health system needs to become prepared to receive survivors with different neuropsychiatric symptoms, including anxiety and depression.”