How has the pandemic affected the mental health of young people?
Lockdowns and school closures during the coronavirus pandemic are not only unpleasant memories for many young people – they have also had an increasing impact on their mental health. No wonder: social contacts were reduced, life was suddenly artificially restricted. Even those who had no problems at home suffered. More and more studies show that these are not just obvious assumptions, but that mental health was affected more often than average.[1]
Overall, the risk of mental health problems rose from 18 percent before the coronavirus pandemic to 30 percent during the pandemic. All of this led to an increase in illnesses: for example, during the school closures,[3] Children and adolescents show general signs of depression 75 percent more often than before.
A new study is now causing a stir with an interesting finding: The scientists believe they have found signs that the cerebral cortex of adolescents – especially girls – has matured untypically quickly during the pandemic years.
What does the new study on brain development during the pandemic show?
In the now in the trade magazine Proceedings of the National Academy of Sciences published study[4] In 2018, scientists at the University of Washington took MRI scans of the brains of 160 children and adolescents. The researchers originally wanted to take MRI scans again in 2020 to study brain development. But then the corona pandemic and the lockdowns got in the way.
They only took a second MRI scan of the brain of 130 of the 160 children and adolescents in 2021 and 2022. And in light of the pandemic, they changed the question: “What did it mean for our teenagers to be at home and not in their social groups – not at school, not doing sports, not in their free time?” says biomedical scientist Neva Corrigan, the lead author of the study. That is what the focus should now be on: to what extent life restricted by the pandemic was reflected in brain structure.
The result is alarming at first glance: When comparing the images, the scientists came to the conclusion that the thickness of the test subjects’ cerebral cortex had decreased more quickly than is typical for normal development – in other words, brain development had progressed more quickly. According to the researchers, this applies particularly to the girls: they were 4.2 years “further” in their development than is normally the case, while for the boys the researchers found it was 1.4 years.
What difference does it make whether the cerebral cortex is thick or thin?
The cerebral cortex is thickest in childhood, then it becomes increasingly narrower. This is probably because nerve connections that are not used break down over time. The fact that the thickness of the cerebral cortex decreases during adolescence – particularly during puberty and the years after – is therefore completely normal; it happens as part of the natural development of the brain. The consequences for the psyche when this development occurs prematurely and at an accelerated rate have not yet been sufficiently researched.
However, the study authors assume that the accelerated thinning of the cerebral cortex is associated with an increased risk of developing mental illnesses and behavioral disorders. In fact, a particularly thin cerebral cortex is associated with mental illnesses such as depression and schizophrenia. However, it is difficult to draw the line as to whether this is a pathologically thin cerebral cortex or whether it is just the thinning of the cerebral cortex during adolescent development.
How do other scientists assess the study on the effects of the pandemic?
“Basically, the idea of investigating the effects of the COVID-19 pandemic – or the presumed stress caused by the lockdown measures – is very interesting,” says neuroscientist Dr. Sofie Valk from the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig. But according to Valk, there are a number of problems with implementing the study: “The study leaves many questions unanswered and cannot substantiate its statements well.” One of the reasons: The number of test subjects is very small. The 130 children and adolescents who had two MRI scans taken had to be divided into different subgroups, including by gender.
“The children and adolescents in the study are of very different ages, and there are also individual differences in maturation. The data do not allow us to draw any conclusions as to whether the changes in the thickness of the cerebral cortex are really different than expected,” says Valk.
It has also been criticized that the researchers did not collect behavioral data on the young people: who had psychological problems and who did not? This data could then have been linked to brain development and the thickness of the cerebral cortex. “I don’t understand why they didn’t do that,” says Valk.
The finding that the acceleration of brain development is particularly pronounced in girls is also viewed critically in view of the small number of subjects. “The study is provocative in assuming that the brains of teenage girls are somehow more vulnerable than those of boys. The data also do not fit well with previous findings on this topic,” says Lise Eliot, Professor of Neuroscience at the Stansin Toshik Center for Brain Function and Repair at Rosalind Franklin University in Illinois, USA.
What conclusions can be drawn from the study?
The fact that the maturation of the cerebral cortex was accelerated by the stress during the corona pandemic and the lockdowns is actually a possibility that has been brought to the attention of researchers by the new study. However, the study itself only provides indications of such an influence on brain maturation by the pandemic – it cannot prove it. This is also because the accelerated brain development of the test subjects cannot be proven, but can only be assumed.
