Pandemic stress physically aged teenagers’ brains, study finds

Stress caused by the coronavirus pandemic has physically altered teenagers’ brains to appear several years older than they are, a new study has found.

In the first year of the pandemic, reports of anxiety and depression rose by 25 per cent from previous years, according to the World Health Organisation. However, the new research suggests that the impact on adolescents may have been even more significant.

The structure of the human brain changes naturally with age, and during puberty, growth occurs in both the hippocampus and amygdala – areas of the brain controlling access to memories and modulating emotions – while tissues in the cortex also become thinner.

An analysis of MRI scans of 163 children taken before and during the pandemic found that this developmental process sped up in teenagers over the course of the global outbreak and its associated lockdowns.

Until now, these kinds of accelerated changes in “brain age” have appeared only in children who have experienced chronic adversity, whether from violence, neglect, family dysfunction, or a combination of multiple factors, according to first author Ian Gotlib, of Stanford University.

“We already know from global research that the pandemic has adversely affected mental health in youth, but we didn’t know what, if anything, it was doing physically to their brains,” said Professor Gotlib.

While these experiences are linked to poor mental health outcomes later in life, it’s unclear whether the changes in brain structure that the Stanford team observed are linked to changes in mental health, Prof Gotlib said.

“It’s also not clear if the changes are permanent,” he said. “Will their chronological age eventually catch up to their ‘brain age’? If their brain remains permanently older than their chronological age, it’s unclear what the outcomes will be in the future.

“For a 70 or 80-year-old, you’d expect some cognitive and memory problems based on changes in the brain, but what does it mean for a 16-year-old if their brains are ageing prematurely?”

The study, initiated before the arrival of Covid-19, was originally intended to analyse depression during puberty, and the researchers – after suffering delays to their research due to the emergence of the virus – then realised they were unable to statistically correct for the pause after discovering the pandemic-related changes to the brain structure of their participants.

“That technique only works if you assume the brains of 16-year-olds today are the same as the brains of 16-year-olds before the pandemic with respect to cortical thickness and hippocampal and amygdala volume,” said Prof Gotlib said. “After looking at our data, we realised that they’re not.

“Compared to adolescents assessed before the pandemic, adolescents assessed after the pandemic shutdowns not only had more severe internalising mental health problems, but also had reduced cortical thickness, larger hippocampal and amygdala volume, and more advanced brain age.”

“The pandemic is a global phenomenon – there’s no one who hasn’t experienced it,” he added. “There’s no real control group.”

Co-author Jonas Miller, of the University of Connecticut, suggested that the findings could have serious consequences for an entire generation of adolescents later in life.

“Adolescence is already a period of rapid reorganisation in the brain, and it’s already linked to increased rates of mental health problems, depression, and risk-taking behaviour,” Professor Miller said.

“Now you have this global event that’s happening, where everyone is experiencing some kind of adversity in the form of disruption to their daily routines – so it might be the case that the brains of kids who are 16 or 17 today are not comparable to those of their counterparts just a few years ago.”

Prof Gotlib hopes to study the same participants into young adulthood, to track whether the pandemic has changed the trajectory of their brain development in the longer term.

He also plans to track the mental health of these teenagers and will compare the brain structure of those who were infected with the virus with those who weren’t, in the hope of identifying any differences that may have occurred.