Teenagers’ brains aged years in a matter of months during the stress and isolation of the pandemic lockdowns.
A new study published in the journal Biological Psychiatry Global Open Science suggests that the pandemic caused similar effects to emotion and decisionmaking centers in the brain as chronic, toxic stress.
Researchers began tracking the development of more than 200 9- to 13-year-olds in Santa Clara County, Calif., in 2016. A ten-months-long lockdown in 2020 put that work on hiatus, but also created a natural experiment to test how the students were affected by the widespread social isolation, school disruption, financial instability, and health stresses.
“Every adolescent in the country went through the pandemic. ... and this is what we’re seeing as a consequence of having experienced yearlong lockdown,” said Ian Gotlib, professor and director of the Neurodevelopment, Affect, and Psychopathology Lab at Stanford University and lead author of the study. “We know that early adversity and stress can accelerate biological aging and brain maturation. It wasn’t so much the direction of the brain aging that surprised us; it was how pronounced it was for such a relatively short period of time.”
Compared to teenagers coming of age before the pandemic, those who experienced 10 months of lockdowns in 2020 showed three to four years of premature aging in the brain’s amygdala, hippocampus, and cerebral cortex.
Stress ‘aging’ in the brain
The cerebral cortex—the tightly folded bundle of neurons that makes up the outer layer of the brain—is associated with higher reasoning, language, and memory. It naturally thins as people age. Similarly, the hippocampus, also associated with concentration, learning, and memory, and the amygdala, associated with emotional regulation and impulse control, grow as children mature.
However, prior studies have shown that children who experience severe adversity, such as abuse or neglect, show premature aging, seen in thinned cortices and swelled amygdala and hippocampic regions of the brain. When related to toxic stress, these changes are in turn associated with higher risk of memory and learning problems and mental illnesses such as anxiety and depression—which may help to explain the sharp rise in mental health disorders among teenagers since the pandemic.
“It may not mean all that much that a 15-year-old’s brain looks like the brain of an 18- or 19-year-old,” Gotlib said. “But it’s the anxiety and depression and suicidal ideation and sadness and fearfulness—that spike that we’re seeing in the deterioration of mental health that I think is so important. And we’ve shown that it’s accompanied by alterations in the brain.”
But Gotlib’s findings don’t mean that teenagers won’t be able to recover academically or emotionally post-pandemic. Brain plasticity—the ability to adapt to new information and environments—isn’t really that different among adolescents of different ages.
Rather, he said, “I would want [school staff] to pay attention to the mental health data and be sure that they’re trying to support teens who are showing signs of emotional distress in any way that they can.”
In one recent survey, adolescents overwhelmingly report anxiety, depression, and stress have become their biggest barriers to learning.
Gotlib and his team plan to scan the teenagers again as they turn 20, to determine whether their brains return to their pre-pandemic developmental trajectory or if the changes continue over time. “We don’t know if this is going to persist or if this is simply a temporary response to the stress of a pandemic,” he said. “The accelerated aging could slow to put them back on track to their chronological age.”
They have already been able to predict which teenagers would be more resilient to pandemic stress based on their previous neurological development; for example, those who had more stable brain development previously were less likely to internalize toxic stress through depression.
The researchers are also starting to work with another team in Singapore, which has been tracking developmental changes to younger children during the pandemic.
