"Don’t stress me out!"
The way in which young people deal with mental health problems depends, among other things, on the structure of their brain – or, to be precise, on the presence of a well-developed protective layer for neurons, the myelin sheath.
Whether it be bullying at school, constant conflict at home, or traumatic experiences, some young people are able to cope well with such stresses, while for others they cause enormous problems. Such experiences can even lead to the development of mental illnesses. But what is the reason for the different responses to these experiences?
With better myelination, the better you are able to deal with stress.
One assumption is that there could be a connection between brain structure and the resilience of teenagers – in other words their ability to deal with stressful situations. Sofie Valk and Meike Hettwer from the Jülich Institute of Neuroscience and Medicine (INM-7) and the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig have been investigating this matter together.
“We were particularly interested in changes in mental health in response to current stressor levels or traumatic experiences – such as the death of a grandmother, and how this in turn relates to the brain structure of adolescents,” explains Valk.
Behind this is the fact that the brain is heavily remodelled during adolescence. In particular, the cognitive networks are restructured and formed. Thinking becomes more complex, and the ability to fit into a social environment improves. However, these changes are usually accompanied by an increase in vulnerability. As a result, adolescents might become more unstable and susceptible to negative environmental influences.
For their research, the scientists used a publicly available data set from Cambridge and London. The data set includes the results of two surveys (conducted at intervals of one to two years) of 14- to 24-year-olds regarding their situation at home, their circle of friends, and the traumas they have experienced so far. The data also include two magnetic resonance imaging (MRI) scans of the brain for each subject, taken at the time of the surveys.
More and more young people affected
Depression, eating disorders, anxiety – such mental illnesses often first emerge during adolescence and young adulthood. The numbers are rising at an alarming rate: in 2022, almost one in five hospitalizations (19 %) of 10 to 17-year-olds was due to mental illness, compared to only 13 % in 2012. Most often, the young people were treated for depression.
Brain scans analysed
“While some young people reported feeling well despite difficult circumstances, others spoke of great stress caused by external factors,” reports Valk. To find out how the mental health of the test subjects is linked to the brain, the researchers analysed part of the data set in more detail. They analysed the MRI scans of 141 subjects who were able to cope better or worse with psychosocial stress over time, i.e. those who became more resilient or more vulnerable with age.
The researchers took a closer look at a specific part of the brain: the myelin sheath. Myelin consists of proteins and fats and forms a protective layer around the extensions of neurons. It stabilizes and insulates the network connections, ensuring that nerve signals can travel freely, quickly, and efficiently from cell to cell.
During adolescence, the myelin sheath is still being developed. The researchers discovered an interesting connection between MRI proxies of myelin content and the ability to adapt to difficult circumstances. Adolescents who were able to cope better with difficult circumstances over time showed stronger myelination in certain brain regions. “There is clearly a connection between resilience and myelin development,” says Valk. “The resilience and ability of adolescents to adapt to psychosocial stressors appears to have a direct influence on brain development. And the reverse is also true: with better myelination, the better you are able to deal with stress.”
In addition to the myelin sheath, the scientists also used the MRI data to study the functional networks in the brain, specifically which brain structures and regions were closely interlinked when the subjects were at rest in the MRI scanner. The results revealed that adolescents who became more resilient over time not only showed stronger regional myelination, but that the cognitive networks in these areas also remained more stable. This means that the connections between the brain regions changed only slightly.
By contrast, the networks in adolescents who became more susceptible to stress over time and showed weaker myelination were less stable and changed more. In other words, this could mean that their brains were more vulnerable to negative external influences and that the adolescents were not as resilient.
Unresolved questions
The extent to which the results might help to strengthen young people’s resilience still needs to be investigated. “For us, it is an important finding that the different ways in which young people deal with stressful situations are also reflected in the development of their brains,” says Valk. “It is possible that myelination and the stabilization of the networks in the brain can be improved by psychosocial support services such as talk therapy or sports programmes. This also needs to be investigated.”
This article is published in effzett 2/2024. Text: Janine van Ackeren
