Stress from the pandemic caused teenagers' brains to age quicker

Stressed teenager - Javi Sanz/iStockphoto
Stressed teenager - Javi Sanz/iStockphoto

Teenagers’ brains aged quicker than normal during the pandemic, scientists have found.

The brain of an adolescent changes as the person enters adulthood, with some regions becoming larger and more developed.

But in children who have been subjected to extreme stress such as violence, abuse or neglect this process happens quicker than normal.

Evidence from scientists at Stanford University who performed brain scans on 163 children before and after the pandemic now shows this process also happened in teens during the Covid pandemic.

“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 Ian Gotlib, the study author.

During puberty and early teenage years the brains of adolescents change with increased growth in the hippocampus and the amygdala, two areas of the brain that control access to certain memories and also modulate emotions.

Unclear if pandemic changes can be reversed

At the same time, tissues in the cortex - an area involved in "executive functioning" - become thinner.

Prof Gotlib said that, until now, such accelerated changes in "brain age" have appeared only in children who have experienced "chronic adversity".

But it is unclear what the long-term ramifications are of these physiological changes to the brain and if the pandemic changes can be reversed.

“If their brain remains permanently older than their chronological age, it's unclear what the outcomes will be in the future,” Prof Gotlib said.

"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?"

Originally, Prof Gotlib explained, his study was not designed to look at the impact of Covid-19 on brain structure.

Before the pandemic, his lab had recruited a group of children and adolescents from around the San Francisco Bay Area to participate in a long-term study on depression during puberty.

But the pandemic disrupted this and meant that the study was a year behind schedule when the scanning resumed and this reset the entire study.

"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,” Prof Gotlib said.

Findings could have 'major implications' for future studies

Prof Gotlib said the findings could have "major implications" for other studies that have spanned the pandemic.

If youngsters who experienced the pandemic show accelerated development in their brains, scientists will have to account for that "abnormal" rate of growth in any future research involving this generation.

"The pandemic is a global phenomenon - there's no-one who hasn't experienced it. There's no real control group,” he said.

Dr Jonas Miller, the study co-author, said the findings might also have "serious consequences" for an entire generation of adolescents later in life.

Dr Miller, now an assistant professor of psychological sciences at the University of Connecticut, added: "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.

"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."

The study is published in the journal Biological Psychiatry.