• Posted September 10, 2024

Pandemic Isolation May Have Caused Rapid Brain Aging in Teen Girls

New research uncovers a possible reason why teenaged girls struggled so mightily with their mental health during the pandemic: Scans showed their brains aged far faster than expected during that stressful time, even faster than the brains of their male peers.

In the study, published Monday in the Proceedings of the National Academy of Sciences, scientists measured cortical thinning, a process where redundant brain synapses are pruned and the outer layer of the cortex is thinned.

While some experts believe this process is simply the brain rewiring itself for efficiency as it matures, it is known to accelerate in stressful conditions. That speeded thinning is also linked to depression and anxiety.

How did the researchers discover that unusual thinning?

After pandemic shutdowns started to lift, scans taken in 2021 showed that both boys and girls had experienced rapid cortical thinning during that period. But the thinning was far more pronounced in girls, whose thinning had accelerated, on average, by 4.2 years ahead of what was expected. Meanwhile, the thinning in boys’ brains had accelerated only 1.4 years ahead of what was expected.

The greater impact on female brains could have been be due to differences in the importance of social interaction for girls versus boys, said senior study author Patricia Kuhl, director of the Institute for Learning and Brain Sciences at the University of Washington. Teenaged girls rely more heavily on emotional relationships with other girls, while boys tend to gather solely for physical activity, she noted.

“Teenagers really are walking a tightrope, trying to get their lives together,” Kuhl explained in a university news release. “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. 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.”

While the evidence abounds that the well-being of teenagers took a big hit during the pandemic, the study offers physical evidence of the damage.

Still, some experts warned against assuming that accelerated cortical thinning is a danger sign.

Thinning is “not necessarily an indication of a problem,” and can be “a sign of maturational change,” Dr. Ronald Dahl, director of the Institute of Human Development at the University of California, Berkeley, told the New York Times. “Accelerated thinning is being interpreted as problematic, and it could be, but that is a leap. ”

In the study, the researchers turned to a group of 160 children and adolescents. They took their first brain measurements in 2018, when their subjects ranged in age from 9 to 17. But pandemic shutdowns prevented them from collecting a second wave of data in 2020.

By 2021, all the young people were emerging from a period of prolonged stress. Around 130 of the youth returned for a second round of testing. The team then compared post-pandemic results with a model that predicted typical brain development in adolescence.

“We were just blown away by the significance of the effects that we found,” study lead author Neva Corrigan told the Times. “The results weren’t subtle. It’s not like we were looking at small changes that were barely there. It was a dramatic shift post-COVID.”

The researchers added that it's not clear whether the changes are permanent.

Dr. Bradley Peterson, a pediatric psychiatrist and brain researcher at Children’s Hospital Los Angeles, said the study had some limitations. The pre- and post-pandemic brain data came from different subsets of the group of youths, so the results do not reflect change in individual subjects’ cortical thickness.

In addition, the authors “offer no supporting evidence” that the changes were directly caused by the social isolation of the lockdown, rather than “any other of a vast number of experiences” that occurred during that period, among them a rise in screen time, an increased use of social media, less physical activity, less classroom time and more family stress.

Regardless of possible limitations, “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.”

More information

KFF has more on teen mental health.

SOURCES: University of Washington, news release, Sept. 9. 2024; New York Times