A new study by University of Washington (UW) researchers found that COVID-19 lockdowns accelerated the aging of teenagers’ brains.
The study, published Monday in the Proceedings of the National Academy of Sciences, found that accelerated brain maturation was particularly pronounced in teenage girls, with a mean acceleration of 4.2 years in females compared to 1.4 years in males.
The teenagers’ brains demonstrated signs of cortical thinning — described by The Telegraph as “a natural process that happens with age and [that] can be accelerated by stress.”
According to the study, MRIs performed on participants’ brains showed that, in girls, all eight lobes sustained accelerated maturation, while significant cortical thinning was noted in 30 distinct regions. Teenage boys showed cortical thinning in just two regions.
According to The Guardian, “Many affected areas underpinning social cognition with roles in processing emotions, interpreting facial expressions and language comprehension” were affected in teenage girls — areas which “are critical for communication.”
Patricia Kuhl, Ph.D., the study’s senior author and co-director of UW’s Institute for Learning & Brain Sciences (I-LABS), told The Guardian her research team was “shocked by these data, that the difference is so dramatic.”
Neva Corrigan, Ph.D., lead author of the study and a researcher at I-LABS, told Euronews the study represents “just another piece of evidence that lockdowns had consequences that weren’t anticipated by policymakers.”
“We know that their academic performance suffered and kids are still suffering the consequences from that,” Corrigan said. “We know that there has been an increased incidence in neuropsychiatric disorders, anxiety and depression, in people who experienced the pandemic, and I think it just points to the real importance of mental health support in our communities for young adults.”
Brian Hooker, Ph.D., chief scientific officer for Children’s Health Defense, told The Defender the study “is a horrifying testament to the significant damage caused by lockdowns, among other draconian measures, from the COVID-19 era.”
“The empirical evidence here for neurological harm is easily predictable considering the extreme and wrong-headed nature of closing off this population from social interaction and in-person learning,” Hooker said.
“As a university professor, I saw this effect firsthand in students after lockdowns had finally been lifted. The level of PTSD and other psychological damage in these individuals was obvious,” Hooker added.
Dr. Kat Lindley, a family medicine physician and president of the Global Heath Project, told The Defender, “It has been known that stress and anxiety can affect neuroplasticity of the brain, so the study finding that lockdowns caused the thinning of the cortex in adolescents is not surprising.”
For Lindley, “The alarming finding was the acceleration of this process and the possible effect it may have on their future development.”
Society ‘failed’ at protecting children during the pandemic
According to The New York Times, “Thinning of the cortex is not necessarily bad; some scientists frame the process as the brain rewiring itself as it matures, increasing its efficiency.”
But the process is also “known to accelerate in stressful conditions, and accelerated thinning is correlated with depression and anxiety,” according to the Times, while according to UW, these disorders “often emerge during adolescence — with females at a higher risk.”
“Adversity in early life is known to speed up cortical thinning in adolescents and it has been linked to an increased risk of neuropsychiatric and behavioural disorders such as anxiety and depression,” The Telegraph noted.
“While the cerebral cortex thinning is part of normal development, the accelerated rate observed might have implications for cognitive functions, emotional regulation and mental health,” Lindley said.
“The big question is whether this could lead to earlier onset of long-term mental issues like chronic depression and anxiety,” she added. “The other important question that must be answered is the long-term effect on cognitive development. There is no doubt that as a society we failed at our most important job, which is to protect our children.”
The study found that, in teenage girls, the regions that sustained the most cortical thinning were the bilateral fusiform, the left insula and the left superior temporal cortex — all of which are linked to social cognition.
“The fusiform is where the brain recognises and processes faces to allow for appropriate interactions in social situations; the insula is crucial in the processing of social and emotional experiences, as well as empathy and compassion; and the temporal cortex is vital to language processing,” The Telegraph reported.
‘Girls suffered more’ from COVID lockdowns
According to The Guardian, while other studies have linked premature brain aging to COVID-19 pandemic measures, the UW study “is the first to reveal stark differences between boys and girls.”
For instance, a 2023 study funded by the National Institute of Mental Health found that the COVID-19 pandemic was associated with accelerated brain development and worsened mental health in teenagers — including higher rates of anxiety and depression.
The UW study began in 2018, originally as a longitudinal, or long-term, study examining changes in brain structure during typical adolescence. The cohort included 160 subjects between the ages of 9 and 17.
The onset of the COVID-19 pandemic changed the researchers’ plans, however, as pandemic-related restrictions such as lockdowns and social distancing meant that it was no longer viable to study typical brain development with this cohort.
Instead, the researchers used the 2018 data to develop a model of expected cortical thinning in teenagers. According to Newsweek, the researchers subsequently performed new scans of the teenagers’ brains in 2021 “to compare how their brains had actually changed during this period.”
Comparing the results with the expected trajectory of cortical thinning for teenagers, the researchers were able to identify the effect of lockdowns and social isolation during the pandemic on the teens’ brain maturation.
“Once the pandemic was underway, we started to think about which brain measures would allow us to estimate what the pandemic lockdown had done to the brain,” Corrigan said in a UW statement. “What did it mean for our teens to be at home rather than in their social groups — not at school, not playing sports, not hanging out?”
According to Kuhl, the greater impact on teenage girls’ brains may be due to the stronger role of social interaction for them. Teen girls often rely more on social relationships with other girls, talking to each other and sharing feelings, while teen boys often prefer to gather with other boys for physical activity.
“What the pandemic really seems to have done is to isolate girls,” Kuhl said. “All teenagers got isolated, but girls suffered more. It affected their brains much more dramatically.”
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‘Possible to imagine’ brain maturation will remain accelerated in these teens
Kuhl said that the teenagers’ cerebral cortex is unlikely to get thicker again, but the return of normal social interactions might result in slower thinning.
“On the other hand, it’s also possible to imagine that brain maturation will remain accelerated in these teens.”
According to Kuhl:
“Teenagers really are walking a tightrope, trying to get their lives together. … They’re under tremendous pressure. Then a global pandemic strikes and their normal channels of stress release are gone. Those release outlets aren’t there anymore, but the social criticisms and pressures remain because of social media.”
While the UW researchers highlighted lockdowns as a key factor affecting the teens’ brain development, Lindley said school closures are likely to have also played a significant role.
“It appears that some of the reasons for these changes have most likely been caused by the change to virtual learning, reduced physical social interactions, increased screen time, and heightened stress due to the uncertainty and changes brought by the lockdown,” Lindley said.
“Social isolation and the lack of typical adolescent activities might have played a role in altering brain development patterns as well,” Lindley added.
“The pandemic provided a test case for the fragility of teenagers’ brains,” Kuhl said. “Our research introduces a new set of questions about what it means to speed up the aging process in the brain. All the best research raises profound new questions, and I think that’s what we’ve done here.”
Ian Gotlib, Ph.D., a professor of psychology at Stanford University and lead author of the 2023 National Institute of Mental Health study, told The Guardian, “It’s important to recognise that although the pandemic is largely over, the effects of the stress of the pandemic are still there for children and adolescents.”
Kuhl told The Guardian that more studies are needed to determine whether brain aging affects cognitive performance over time.
The authors noted in the study that its findings “highlight the importance of providing ongoing monitoring and support to adolescents who experienced the pandemic lockdowns.”