Girls who survived the Covid-19 lockdown have brains that age faster than boys, with data suggesting social restrictions have had a disproportionate impact on them.
MRI scans found evidence of premature brain aging in both boys and girls, with girls’ brains on average 4.2 years older than expected after the lockdown, compared to 1.4 years older in boys.
It’s unclear whether the changes have negative consequences, but the findings have raised concerns that they could harm adolescents’ mental health and learning ability.
“We were shocked by these data, the difference is so dramatic,” said Prof. Patricia Kuhl, co-director of the Institute for Learning and Brain Sciences at the University of Washington in Seattle.
The researchers collected MRI scans from 160 9- to 17-year-olds in 2018 and used them to build a model of how the brain’s cortex normally thins during the school years. Some cortical thinning is natural and an important part of the brain’s maturation and specialization in adolescence.
The team revisited the same group in 2021 and 2022, after the lockdowns, and collected new MRI scans from individuals aged 12 to 16. Compared with pre-pandemic brain development, these showed signs of accelerated cortical thinning in one region of the boys’ brains and in 30 of the girls’ brains, across both hemispheres and all lobes.
Other researchers have linked premature brain aging to the pandemic, but the latest study, in Proceedings of the National Academy of Sciencesis the first to show clear differences between boys and girls.
Both sexes showed signs of accelerated aging in a brain region linked to vision, which may affect the processing of faces. But in women, the brain changes were widespread. Many of the affected areas support social cognition, with roles in processing emotions, interpreting facial expressions and understanding language, which the researchers say are crucial for communication.
Kuhl believes the difference reflects girls’ greater reliance on social groups and interactions. “Girls chat endlessly and share their emotions,” she said. “They are much more dependent (than boys) on the social scene for their well-being and for their healthy neural, physical and emotional development.”
More studies are needed to see whether brain aging affects cognitive performance, but Kuhl notes that premature cortical thinning has been linked to early-life adversity and a greater risk of neuropsychiatric disorders. Cortical thinning is crucial for the brain to specialize, but it comes with a loss of cognitive flexibility that could potentially impact learning.
Kuhl said the findings were a “reminder of the vulnerability of teens” and suggested parents talk to their teens about their experiences of the pandemic. “It’s important that they invite their teens for a cup of coffee, for a cup of tea, for a walk, to open the door to conversation,” she said. “Whatever it takes to open them up.”
“It’s important to recognize that even though the pandemic is largely over, the effects of the stress of the pandemic are still being felt by children and adolescents,” said Ian Gotlib, a professor of psychology at Stanford University who has reported similar changes in the brain. “Ensuring that young people have support for their mental health is critical, perhaps now more than ever.”
“This adds to our understanding that adolescents have experienced accelerated brain changes as a result of the Covid-19 pandemic,” said Dr. Lina van Drunen, a researcher at Leiden University in the Netherlands, who reported similar changes in the brain in adolescentsIdentifying the specific factors behind premature aging and understanding the long-term consequences were now crucial, she added.