NA while ago, Mark Chiverton, a 33-year-old from the UK, found he was making a lot of silly mistakes. He would mix up words when writing emails, or forget a basic word when talking to his wife. None of these mistakes were that worrying in themselves – but they were happening so often that Chiverton began to worry that he was, simply put, “becoming stupid.”
“At first I thought, ‘Maybe it’s normal aging, or maybe I banged my head and didn’t realize it,’” he says. But eventually, a thought occurred to him: Could COVID-19 be the cause of his mental defeats? Chiverton thinks he had the virus in early 2020, when testing wasn’t widely available, and he’s pretty sure he’ll have it in 2022. Though he hasn’t suffered any physical effects from those infections (and there are periods when his brain spasms resolve), he sometimes wonders if these mental defeats are mild symptoms of long COVID, the name for chronic symptoms that follow an infection.
He's not alone in experiencing these problems – and he may not be wrong to blame Covid-19 for them. In the US alone, nearly one million more working-age adults reported having serious difficulty remembering, concentrating or making decisions in 2023 than before the pandemic, according to a New York study. Times Analysis of Census Bureau data.
Not every mental mistake is cause for concern, says Andrew Petkus, MD, associate professor of clinical neurology at the University of Southern California's Keck School of Medicine. Mistakes like forgetting why you came into a room or being late to an appointment can be a perfectly normal part of being a busy, distracted, and often under-rested human being. Even if you've done things like these before and thought of them as nothing special, they can seem more significant after a life-changing event like the pandemic. “If we didn't have COVID, you could still forget,” Petkus says.
Still, it's not strange to think the pandemic has taken a toll on our brains, says Jonas Wibel, a cognitive and behavioral neuroscientist at the University of Hawaii at Manoa. Wibel is currently trying to measure post-Covid inflammation and nerve damage in the brains of people who report symptoms like brain fog, lethargy or low energy. When he began publicizing the study, he says, “I got a lot of emails from a lot of people saying the same thing”: that they never fully recovered after the pandemic.
But why? It's probably a mix of several things, says Wibel. The SARS-CoV-2 virus can affect the brain directly, as several studies have now shown. But the pandemic may also have affected cognition in less obvious ways. Months or years spent at home, living much of life through screens, may have left a permanent mark. Even though society is now almost back to normal, it may be hard to shake off the trauma of living through a terrible, unprecedented health crisis.
Your brain on SARS-CoV-2
By now it's clear that SARS-CoV-2 isn't just a respiratory virus, but can affect organs throughout the body – including the brain. Researchers are still trying to figure out why this is, but leading hypotheses suggest that SARS-CoV-2 may cause persistent inflammation in the brain, damage to blood vessels in the brain, a disruption in the immune system so much that it affects the brain, or perhaps a combination of all of the above. Studies have also found that people's brains may shrink after having COVID-19, a change possibly linked to cognitive problems.
Covid-19 has been linked to serious cognitive problems, including dementia and suicidal thinking. And brain fog, a common symptom of long Covid, can be so profound that people are unable to live and work as well as they did before. But Covid-19 is also capable of affecting the brain in subtle ways. A 2024 study says this. New England Journal of Medicine The cognitive performance of people who fully recovered from COVID-19 was compared to a similar group of people who had never had the virus. The COVID-19 group performed even worse, equivalent to a drop of about three IQ points.
That's not a dramatic difference. Our cognitive abilities naturally vary a little from day to day — and in an interview with Time in July, study co-author Adam Hampshire, a professor of cognitive and computational neuroscience at King's College London, said the three-point IQ difference is within that normal range of fluctuations, so small that some people might not even notice it.
But could such a decline lead to additional typos and distractions? Perhaps. In the Hampshire study, people who had COVID-19 consistently performed worse on cognitive tests than those who had not.
Wiebel says that if there are “mild but ubiquitous” changes in the brain after infection, those effects could potentially influence the brain, behavior and social behavior in “many subtle, but possibly significant” ways. [cumulatively] Very bad ways.”
Beyond the virus
Even for those lucky enough to never become infected, living through a pandemic can impact the brain.
According to a recent study PNASThe researchers performed a pair of MRI brain scans on a small group of American teens: one in 2018 and one in 2021 or 2022. In those years, they observed significant thinning in parts of the brain of children (and especially girls), including parts that control social cognition functions such as processing facial expressions and emotions. Although the researchers did not analyze the effects of SARS-CoV-2 infections, they concluded that the stress of living during pandemic lockdowns may be responsible for this change, which they compared to an additional four years of brain aging for girls and an additional year for boys.
Stress and trauma have profound effects on the brain. Many studies show that people who experience trauma have a higher risk of cognitive decline as they age. Studies show that stress can also reduce a person's ability to think clearly, reason, and remember.
“COVID was a generational traumatic event,” says USC's Petkus. “Everyone was affected by it.” So, it's possible that a large number of the population suffer from these ill effects of trauma and stress.
Beyond the mental burden of living through a frightening and turbulent time, many people had to give up habits that are good for the brain — like socializing, staying physically and cognitively active, and seeking out new experiences — when they were stuck at home in the early days, Petkus says. It's too early to say whether that dramatic but short-term period will have long-term effects — but four years after the virus emerged, some things still aren't the same as they were.
For example, student test scores are improving but still not back to pre-pandemic levels; the declines have been particularly dramatic in low-income school districts as well as in schools that had long periods of remote learning, says Sean Reardon, a professor at Stanford University’s Graduate School of Education and one of the leaders of the Education Recovery Scorecard, a research project focused on learning loss caused by the pandemic. The long recovery process likely reflects a combination of several things, Reardon says: Not only did kids miss out on attending school in person for a while, but they also experienced seismic disruptions to their lives, endured a period of significant stress and anxiety, and are now being asked to learn new material in school while making up for pandemic-related learning gaps.
“Getting behind in math or reading skills isn't really a change in your intelligence,” Reardon says. “It's a change in your skills, in how much you've had the opportunity to learn.”
It's hard to say whether the same trend would be seen in adults, because adults don't take standardized tests in the workplace every year. Adults certainly face the same mix of stress, trauma, boredom and loneliness as children — but Reardon says he thinks it may be easier for adults to recover, because they've already developed the skills that allow them to perform complex tasks.
Returning to normal
Petkus agrees, “There may have been a setback for a few years, but things are getting back to normal now.”
Petkus says people who feel their brains melting a bit during the pandemic may benefit from adopting or resuming brain-boosting habits they picked up during Netflix-fueled lockdown, such as social interaction and mental and physical exercise. The effects of stress and trauma can often be balanced with social support and healthy coping strategies, he says. People who recover well from difficult events sometimes experience what's known as post-traumatic growth, a blossoming of their mental and emotional health after a difficult period.
It's hard to say whether brain changes caused directly by SARS-CoV-2 infection are reversible, as researchers are still studying this question. But there are some positive signs. Some potential causes of chronic brain fog — such as persistent inflammation or damage to blood vessels — are theoretically reversible with the right treatment.
Even Hampshire's study on IQ differences after Covid had cause for optimism. Hampshire's team found that people with long Covid symptoms were on average about six IQ points lower than those who never had Covid-19. But people whose long Covid symptoms resolved over time also saw improvements in their cognitive scores.
He said the findings were “very positive”. “It may give some hope to people who are struggling.”