COVID-19 lockdowns linked to accelerated brain aging in adolescents, particularly in girls

A longitudinal neuroimaging study of adolescents found that their brains underwent accelerated aging between 2018 and 2021, during the COVID-19 pandemic lockdowns. This was evidenced by increased thinning of the cortex region of the brain in these individuals. On average, brains of girls aged an additional 4.2 years during this period, while brains of boys aged an additional 1.4 years. These findings were published in the Proceedings of the National Academy of Sciences and shed light on the potential neurological impact of prolonged social isolation and stress during the pandemic.

Brain age refers to the biological condition of the brain, which can differ from an individual’s chronological age. Advanced neuroimaging techniques such as MRI, EEG, or PET scans, combined with machine learning algorithms, are used to assess brain age by analyzing structural, functional, and connectivity patterns in the brain. Key factors such as gray matter volume, cortical thickness, and white matter integrity are measured to estimate brain age. When brain age surpasses chronological age, it may indicate heightened risks for cognitive decline, mental health issues, or neurological conditions.

Cortical thinning, the gradual reduction in the thickness of the brain’s outer layer, is a normal part of adolescent brain development. It reflects processes like synaptic pruning and myelination, which fine-tune the brain for more efficient functioning. However, this process can accelerate under adverse conditions, including chronic stress, sleep deprivation, poor diet, and medical issues like hypertension or diabetes. Accelerated cortical thinning is associated with greater vulnerability to neuropsychiatric disorders, including anxiety and depression, especially during adolescence.

The study, led by Neva M. Corrigan of the University of Washington, aimed to investigate the impact of the COVID-19 pandemic lockdowns on adolescent brain structure and aging. Governments worldwide implemented lockdown measures in 2020 and 2021 to mitigate the spread of the virus. These restrictions disrupted everyday life, forcing individuals to stay at home and limit social interactions. For adolescents, a developmental stage heavily reliant on peer relationships and social experiences, this isolation likely introduced significant stress.

The study recruited 87 adolescents, aged 9–17, who underwent MRI brain scans in 2018 as part of an earlier project on typical brain development. These participants returned for follow-up scans three years later, in late 2021 and early 2022. The researchers compared changes in cortical thickness over this period against statistical models predicting normal aging patterns based on the pre-pandemic data.

The results showed that participants experienced faster cortical thinning than expected over the three years. In boys, the additional thinning corresponded to 1.4 years of accelerated brain aging. Girls, however, exhibited a more pronounced acceleration, with their brains showing an additional 4.2 years of aging.

The thinning in girls’ brains was widespread, affecting multiple regions across both hemispheres and lobes, including areas critical for social and emotional processing, such as the fusiform gyrus and superior temporal cortex. In boys, the thinning was more localized, primarily affecting the visual processing regions. The disparity may be linked to the heightened reliance of adolescent girls on peer relationships for emotional support, which was disrupted during the lockdowns.

“In summary, the findings of the present study suggest that the lifestyle changes associated with the COVID-19 pandemic lockdowns resulted in a deviation from the normal pattern of cortical thinning during adolescent development and that the effects were more dramatic in females than in males. As accelerated cortical thinning during brain development is associated with increased risk in the development of neuropsychiatric and behavioral disorders, the findings from this study highlight the importance of providing ongoing monitoring and support to adolescents who experienced the pandemic lockdowns,” the study authors concluded.

The study makes an important contribution to the scientific understanding of possible repercussions of the COVID-19 lockdowns. However, it should be noted that the observational design of the study does not allow for cause-and-effect conclusions. The accelerated cortical thinning observed may have been influenced by factors beyond the lockdowns, such as individual differences in stress levels, family dynamics, or pre-existing conditions.

Additionally, the sample size was relatively small, limiting the generalizability of the findings. Behavioral data, such as detailed assessments of participants’ stress levels, sleep patterns, and physical activity during the lockdowns, were not collected. These measures could provide valuable insights into the specific factors driving accelerated brain aging. Future studies with larger, more diverse samples and comprehensive data collection are needed to build on these findings.

The paper, “COVID-19 lockdown effects on adolescent brain structure suggest accelerated maturation that is more pronounced in females than in males,” was authored by Neva M. Corrigan, Ariel Rokem, and Patricia K. Kuhl.