Lockdowns, put in place to try to combat the Covid-19 pandemic, have prematurely aged the brains of adolescents, especially girls.
- Lockdowns led to an unusual acceleration of brain maturation in adolescents, a new study finds.
- Brain aging is more rapid in girls. The average acceleration was 4.2 years for adolescent girls and 1.4 years for boys.
- The observed difference between the two sexes could be linked to the importance of social interactions in the daily lives of adolescent girls.
In an attempt to slow the spread of Covid-19 and reduce the strain on hospitals, many countries have opted for lockdowns. The negative impact of this measure on the mental health of adolescents has been widely studied. But new research shows that it also had effects on their brains: it made them age faster. This accelerated maturation was also more pronounced in girls.
The work was conducted by the University of Washington and published in the journal Proceedings of the National Academy of Sciences September 9, 2024.
Brain aging: girls more affected than boys
In 2018, researchers launched a study to assess changes in the brain structure of adolescents because they wanted to learn more about brain maturation, which is measured by the thickness of the cerebral cortex (the outer layer of brain tissue). “The cerebral cortex naturally thins with age, even in adolescents. Chronic stress and adversity are known to accelerate cortex thinning, which is associated with an increased risk of developing neuropsychiatric and behavioral disorders.”explain the authors in their press release.
Scientists rounded up 160 adolescents aged 9 to 17 in 2018 and gave them MRI scans. The cohort was scheduled to undergo further scans in 2020, but due to the pandemic, they were pushed back to 2021.
“Once the pandemic was underway, we started thinking about brain measurements that would allow us to estimate the effects of confinement on the brain,” explains Neva Corrigan, lead author and research scientist at I-LABS. “What did it mean for our teenagers to stay home rather than in their social groups – not in school, not playing sports, not going out?”
Accelerated cortical thinning in young people
To answer these questions, the team created a model of expected cortical thinning during adolescence, based on the initial data. When compared, the new tests showed a general effect of accelerated thinning in young people. However, this was much more pronounced in girls. The average acceleration was 4.2 years for adolescent girls and 1.4 years for boys.
Moreover, the areas affected by maturation also diverged. For girls, the effects of cortical thinning were observed throughout the brain, in all lobes and both hemispheres. For adolescents, they were observed only in the visual cortex.
Brain: Lack of social interactions at the heart of early maturation
Patricia Kuhl, lead author and co-director of the UW Institute for Learning & Brain Sciences (I-LABS), suggests a hypothesis to explain the observed differences in maturation between girls and boys. It could be related to the greater importance of social interactions in the daily life and stress management of adolescent girls. Indeed, they are more focused on relationships with their friends, favoring meetings, discussions and sharing emotions. Boys, on their part, are more likely to gather around physical activities.
“All the teenagers were isolated but the girls suffered more”
“Those ways to relieve stress were gone, but the criticism and social pressures remained because of social media. What the pandemic seems to have really done is isolate girls. All teenagers were isolated, but girls suffered more. Their brains were affected much more.”
The expert adds that it is unlikely that the cerebral cortex will thicken again. But it is possible that there will be some recovery after the return of social interactions and normal outings.
