Many people have complained of mental confusion since recovering from the Coronavirus, and many data indicate the effects of the Covid-19 pandemic on brain function in a percentage of those infected.
In the United States alone, about 1 million working-age adults reported having more serious difficulty remembering, concentrating or making decisions in 2023 than before the pandemic, according to a New York Times analysis of Census Bureau data.
Not every mental glitch is a cause for alarm, Andrew Petkus, an assistant professor of clinical neurology at the Keck School of Medicine of the University of Southern California, tells TIME. Blunders like forgetting why you walked into a room or missing an appointment can be completely normal parts of being busy, distracted, and often under-rested. While you may have done these things before and brushed them off as nothing, they can seem even more significant in the wake of a life-altering event like a pandemic. “If we didn’t have COVID, I probably would have forgotten about it,” Petkus says.
Still, it’s not surprising to think the pandemic has had an impact on our minds, says Jonas Vibel, a cognitive and behavioral neuroscientist at the University of Hawaii at Manoa.
Veibel is currently trying to measure post-Covid inflammation and neurological damage in the brains of people reporting symptoms like brain fog, lethargy or low energy. When he started publishing the study, he said, “I got a lot of emails from a lot of people saying the same thing: They haven’t fully recovered from the pandemic.”
But why? It’s probably a combination of things, says Vibel. SARS-CoV-2 can directly affect the brain, as several studies have now shown. But the pandemic may also have affected cognition in less obvious ways. The months or years spent at home, living much of their lives through screens, may have had negative effects. Even though society is now mostly back to normal, the trauma of living through a terrifying and unprecedented health crisis can be hard to shake.
Brain under Covid
It’s now clear that SARS-CoV-2 is not just a respiratory virus, but one that can affect organs throughout the body, including the brain. Researchers are still learning why, but leading hypotheses suggest that the novel coronavirus may cause persistent inflammation in the brain, damage to blood vessels in the brain, an immune system disorder so severe that it affects the brain, or perhaps a combination of all of the above. Studies have found that people’s brains can shrink after COVID-19, a change that may be linked to cognitive issues.
COVID-19 has been linked to serious cognitive problems, including dementia and suicidal thoughts. Brain fog, a common symptom of long COVID, can be so profound that people are unable to live their lives and work at the jobs they once did. But COVID-19 also appears to affect the brain in more subtle ways. A 2024 study in the New England Journal of Medicine compared the cognitive performance of people who had fully recovered from COVID-19 with that of a similar group of people who had never had the virus. The COVID-19 group performed worse, equivalent to a deficit of about 3 IQ points.
That’s not a huge difference. Our cognitive abilities naturally fluctuate a bit from day to day, and in a July interview with TIME magazine, study co-author Adam Hampshire, a professor of cognitive and computational neuroscience at King’s College London, said a 3-point IQ difference is “within” the range of that normal fluctuation, and is so small that some people might not even notice it.
If the brain suffers “subtle but widespread” changes after injury, says Veibel, those effects could “affect the brain and social behavior in very subtle, but potentially cumulative and very bad, ways.”
What about those who have not been infected with Corona?
Even for the lucky few who haven’t been infected, living through a pandemic can take a toll on the brain.
In a recent study published in the Proceedings of the National Academy of Sciences, researchers conducted pairs of MRI brain scans on a small group of teenagers in the United States: one in 2018 and one in 2021 or 2022. Over those years, they observed significant thinning in parts of the children’s brains (especially girls’), including those that control social cognition tasks like processing facial expressions and emotions.
Although the researchers did not analyze the effects of COVID-19 infection, they concluded that the stress of living through pandemic lockdowns was likely responsible for the change, which they likened to four extra years of brain aging for girls and one extra year for boys.
Stress and trauma have well-documented effects on the brain. Many studies show that people who experience trauma tend to be more susceptible to cognitive decline as they age. Studies suggest that stress can also impair a person’s ability to think clearly, reason, and remember.
“COVID was a generational traumatic event,” Petkus says. “Everyone has been exposed to it.” So the general population is likely to experience some of these side effects from trauma and stress.
How to deal with brain fog?
Those who feel like their brains have been a little off during the pandemic could potentially benefit from adopting or resuming brain-boosting habits, like social interaction and mental and physical exercise, Petkus says. Even the effects of stress and trauma can often be offset with social support and healthy coping strategies, he says. Even people who recover well from difficult events sometimes experience what’s known as post-traumatic growth, a thriving of their mental and emotional health after a difficult period.
It’s hard to say whether the brain changes directly caused by COVID-19 infection are treatable, as researchers are still studying the question. But there are some positive signs. Some potential causes of chronic brain fog, such as persistent inflammation or blood vessel damage, are theoretically reversible with the right treatments.
Long-haul COVID-19 Syndrome
It is noteworthy that last Tuesday (September 17), German Health Minister Karl Lauterbach said that even after the end of the Corona pandemic, there are still people in Germany who are infected with what is known as long-term Covid-19 syndrome or post-Covid-19 syndrome.
During a roundtable meeting in Berlin on the long-term consequences of infection with the coronavirus, “long Covid”, with the participation of representatives from the scientific community, the health sector and infected people, Lauterbach said that “the number of people infected with long Covid syndrome is increasing.”
“Millions of people will be infected again with Covid this winter,” the minister added, noting that some of them will develop symptoms of chronic fatigue syndrome. He explained that the risks are lower for people who have been vaccinated or who have previously been infected with the virus, but they still exist.
Long Covid, or post-COVID syndrome, refers to symptoms that persist or appear after the acute phase of the disease, which lasts for 4 weeks. Symptoms can be severe and occur individually or in clusters. The most common symptom is a feeling of weakness and extreme and persistent fatigue known as “chronic fatigue.” Other symptoms include breathing and lung problems, headaches, difficulty concentrating and memory problems.
According to Lauterbach, the hope for recovery is still slim.
In addition, the care provided to infected patients is still inadequate, according to Professor Carmen Scheibenbogen from the Charité hospital. This physician heads the immunodeficiency clinic at the University Medical Center in Berlin.