Covid lockdowns, such as school closures, canceled sports activities and stay-at-home orders, prematurely aged teen brains by as much as four years, researchers from the University of Washington found.
The new study, published Monday in the Proceedings of the National Academy of Sciences, is more evidence of how disruptions to daily routines may have contributed to behavioral problems, an increase in eating disorders, anxiety and depression in adolescent girls and boys.
Scientists at the university’s Institute for Learning & Brain Sciences (I-LABS) began the study using MRIs in 2018 to see how the brain structure of 160 teens from the Seattle area developed over time. The participants, a nearly equal number of boys and girls, ranged in age from 9 to 19 at the start of the study.
Lead researcher Patricia Kuhl, co-director of I-LABS, said that after Covid lockdowns began in 2020, they couldn’t do brain scan follow-ups until 2021. So they shifted the focus of the study to learn how the lockdowns had affected adolescent brain structure.
By measuring the thickness of the cerebral cortex — the outer layer of tissue in the brain which controls higher level functions of the brain like reasoning and decision-making — they discovered the brains of teen boys had prematurely aged 1.4 years. The brain scans of the girls showed accelerated aging of 4.2 years, according to the study.
The cerebral cortex naturally thins as we age. Chronic stress can also cause similar changes in the brain. But in the three-year period between the first scan and the follow-up, there was much more thinning than the researchers expected.
“As we age, the thinning of the cortex is associated with less fast-processing time, with less flexible thinking, with all of the things that we associate with aging,” Kuhl said. “All of the teens in general showed this accelerated aging.”
For teenage girls the aging was more pronounced. The thinning was found to be widespread throughout the female brain, occurring in 30 regions across both hemispheres and all lobes, the scans showed. In the male brain, the thinning was limited to only two regions, both in the occipital lobe, which affects distance and depth perception, face recognition and memory.
The greater influence on girls could be due to differences in the importance of social interaction for girls versus boys, Kuhl said. Boys tend to gather for sports and physical activity. Adolescent girls may rely on personal relationships for emotional support and self-identity.
“When girls and women are stressed, there is a natural response to get together and talk about it, and we release oxytocin and other neurotransmitters that make us feel better, said Dr. Ellen Rome, head of adolescent medicine at Cleveland Clinic Children’s Hospital. Rome was not involved in the new research.
What does the premature brain aging mean in the day-to-day lives of young people who navigated pandemic restrictions, often alone in their rooms, taking classes over Zoom or missing social connections?
Are there long-term risks for ‘pandemic brains’?
The research doesn’t prove the lockdowns caused the brain changes — mental health disorders were rising among children even before Covid. It does suggest, however, that the thinning of the cortex can be connected to increased anxiety, depression and other behavioral disorders, Kuhl said.
Another brain scan study in 2022 from Stanford University showed similar changes in cortical thickness in teen brains during Covid restrictions. The Stanford researchers compared the stress and disruptions of the pandemic to childhood trauma such as violence, neglect and family dysfunction.
The pandemic was a traumatic time for everyone, Kuhl said. For young people — at a time in their lives when they’re already experiencing intense changes in their emotional and behavioral development — the isolation was even more damaging for their emotional health.
“The pandemic was dramatic and unexpected, of course, but dramatic and catastrophic in a way, not only for physical health, but mental health,” she said.
Since 2021, several reports on youth mental health from the Centers for Disease Control and Prevention revealed unprecedented levels of hopelessness and suicidal thoughts among teenage girls and boys. In early August, a CDC survey released found a small improvement in teen mental health, although 53% of young women in high school say they are still feeling persistent sadness.
In brain development there are periods of time when certain types of learning are most effective, said Dr. Jonathan Posner, professor of psychiatry at Duke University School of Medicine. For example, it’s much easier to learn language as a young child than as an adult.
“The teenage years are hugely important for social development,” said Posner, who was not part of the new study. “If you don’t have those social interactions, there’s just not the opportunity to have that social learning.”
The cortex can’t regrow and continues to shrink throughout life. It’s not yet clear whether the young people’s prematurely aging “pandemic brains” could be at higher risk for disorders like ADHD and depression and, possibly, even diseases like Alzheimer and Parkinson, Kuhl said.
Seattle mom Karin Zaugg Black, 54, saw how the pandemic affected her two children during more than a year of remote school classes. Her daughter Delia, 14, was in seventh grade; Sam, 10, in fourth.
Delia especially felt the loss of social interaction.
“When she reflects back on that time, she was definitely like, ‘Yeah, it was really hard. I felt like I had no friends, and that was really difficult,’” Black said about her daughter’s time during the pandemic.
“Their social skills are behind. You know, sort of they lost that ability to navigate in the social world with their peers,” she said.
The good news is Delia, now a senior in high school, has regained a lot of the social interaction muscle she lost during the pandemic.
Experts say the loss doesn’t have to be permanent if young people’s social interactions and connections have recovered since the pandemic.
“Fortunately, kids are really resilient, and we can get them back out there and help them catch up,” said Posner. “But we also don’t want to deceive ourselves that this was nothing. It had a significant impact on growth and development.”
