A study published yesterday in Proceedings of the National Academy of Sciences, suggests that lockdowns and school closures may have prematurely aged the brains of adolescents—especially girls— who experienced significant stressors and changes in the early months of the COVID-19 pandemic.
The study came from researchers at the University of Washington who began a longitudinal study of magnetic resonance imaging (MRI) of the brain in 160 teens between 9 and 17 years in 2018. The study was originally meant to document age-related structural changes during adolescence. Participants were meant to undergo MRI brain scans every 2 years.
But the study halted in 2020 when the pandemic began. Soon, however, researchers began to see value in looking at the brain during the pandemic, and in 2021, 3 years after the first images, 81% of the original cohort returned for another MRI.
"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," said Neva Corrigan, PhD, lead author and research scientist at the University of Washington’s Institute for Learning & Brain Sciences in a press release from that university. "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?"
They built a model based on 2018 images of what brains scans should have shown in 2021, then compared that result to images taken.
Cortical thinning, especially in females
The authors found significant evidence of excessive and premature cortical thinning, which occurs with age and is accelerated by stress. When compared to the models built using 2018 images, the thinning showed that the first year of the pandemic aged teen brains by 4.2 years for girls and 1.4 years for boys.
The difference in the mean acceleration between girls and boys was 2.8 years.
"Whereas this thinning was found to be widespread throughout the female brain, occurring in 30 brain regions across both hemispheres and all lobes of the brain, we found it to be limited to only two regions in the male brain, both located in the occipital lobe," the authors wrote.
Girls' brains showed significant thinning in the bilateral fusiform, the left insula, and the left superior temporal cortex—all areas of the brain associated with social cognition. The authors speculate that social isolation during the early months of the pandemic hit girls the hardest.
"What the pandemic really seems to have done is to isolate girls. All teenagers got isolated, but girls suffered more. It affected their brains much more dramatically," said Patrica Kuhl, PhD, from the University of Washington.
What the pandemic really seems to have done is to isolate girls.
The cortical thinning, which is associated with depression and anxiety, is unlikely to correct or re-thicken. "It is possible that there might be some recovery," Kuhl said. "On the other hand, it’s also possible to imagine that brain maturation will remain accelerated in these teens."
