Since the start of the pandemic COVID-19, many studies aim to better understand how the virus affects our body in the long term. Some have revealed in particular that even a mild infection with SARS-CoV-2 causes changes in the structure of the brain, including a reduction in volume. A new study, focusing in particular on the impact of stress linked to the pandemic, reveals that the brains of adolescents show signs of early aging, according to post-pandemic MRI scans. Although it is not yet known what the consequences of these changes are, these results show one of the silent consequences of the pandemic in young people and the extent of the psychological impacts.
In previous studies, brain MRI scans of patients who contracted COVID-19 showed structural abnormalities even long (more than 6 months) following infection. These structural changes would have consequences ranging from anxiety to mood disorders, and would also increase the incidence of neurological disorders such as stroke, cerebral hemorrhage and dementia (more frequent consequences for severe cases) .
Most studies on the neurological consequences of SARS-CoV-2 infection focus primarily on adults, and few focus on the impacts in children and adolescents. In the latter, the most frequent post-infection manifestations would be inflammatory damage to the brain (encephalitis, acute encephalomyelitis), spinal cord (myelitis) and cranial and spinal nerves (neuritis).
This new study, published in the journal Bioological Psychiatry : Global Open Science is one of the few to examine the psychological impact of the pandemic on adolescents. It is indeed a critical stage of life, where the brain undergoes a brutal restructuring, generating profound physiological upheavals. It is then interesting to understand how the COVID-19 pandemic can cause neurological changes in adolescents, who are already undergoing profound natural changes due to puberty.
Changes likely related to stress
In adolescents, the sudden change in brain architecture is such that the limbic system develops much faster than the prefrontal cortex. This is one of the reasons why we often observe risky behaviors in adolescents, because the search for the immediate reward is not sufficiently controlled by the prefrontal cortex.
According to the new study, conducted by researchers at Stanford University, these changes would have tended to be more significant coming out of the pandemic period, with signs of premature aging. To arrive at this result, the researchers compared the MRI results of 81 adolescents between November 2016 and 2019 (before the pandemic) with those of 82 others between October 2020 and March 2022 (during the pandemic and following the lifting of restrictions). toilets).
After sorting 64 volunteers from both groups and categorizing them by age and gender, the researchers found that cortex thinning and hippocampus and amygdala growth were greater in the post-pandemic group analyzed. . This process – normal in all adolescents – would thus have accelerated, as if the brain had aged more quickly.
According to the scientists, the difference in brain age would be regarding three years compared to the group having carried out an MRI before the pandemic. ” We did not expect such a large increase given that the lockdown lasted less than a year », is surprised Ian Gotlib, professor of psychology at Stanford University and lead author of the study.
Suspecting early stress effects, the researchers also assessed whether adolescents (in the post-pandemic group) might show symptoms of depression and anxiety. Participants then self-reported greater mental health difficulties, such as greater anxiety and internalizing problems.
« Deteriorating mental health is accompanied by physical changes in teenage brains, likely due to pandemic stress “says Gotlib. According to the expert, these results were consistent with those of previous studies, focused on the impacts of the pandemic in adolescents. However, researchers don’t yet know how these rapid changes might actually affect them. It is not excluded that the consequences can be negative, but nothing yet indicates that they cannot be positive by making the brain more resilient, for example. Additionally, some accelerated changes reported by the research team were linked to higher performance on intelligence tests.
Also, because the brain is an incredibly plastic organ, especially at a young age, things may turn out differently and the changes may fade over time. Large-scale imaging of the brain also cannot provide details regarding small neural circuits. As a next step, the researchers plan to reanalyze the participants (showing post-covid changes) at age 20, to find out more.
