A study published in Nature Communications looks at brain ageing during the Covid-19 pandemic.
Dr Eugene Duff, Advanced Research Fellow in Informatics, Department of Brain Sciences, Imperial College London, said:
“Mohammadi-Nejad and colleagues present a unique analysis of MRI data from the UK Biobank study to identify evidence for the impact of the COVID-19 pandemic period – independent of the infection itself – on brain health and aging. They were able to show that, even in the absence of COVID-19 infection, living through the pandemic was associated with accelerated aging of the brain, and could point to a variety of factors potentially contributing to this acceleration, such as sex and socio-demographic background. With this approach, the authors were able to quantify more extensive brain health associations of the pandemic period than studies focusing purely on effects of the virus itself. However, as an observational study it is not possible to fully exclude that factors unrelated to the pandemic could contribute to the observed acceleration. While the events of the pandemic were exceptional, this work demonstrates the stark effects that the conditions of an individual’s life may have on brain and cognitive health, and the value of careful dissection of the myriad of local and global factors contributing to these conditions.”
Prof Masud Husain, Professor of Neurology & Cognitive Neuroscience, University of Oxford, said:
“While this is a very carefully conducted analysis, we have to be cautious with interpretation.
“The brain age difference between the two groups (as indexed by brain scanning) was on average only 5 months, and difference in cognitive performance between groups was only on the total time taken to complete one of the tests. Is this really going to make a significant difference in everyday life?
“Furthermore, the time between scans was much shorter in the people scanned before and after the pandemic, compared to those who had both scans before the pandemic. We therefore don’t know if brain aging would have recovered if more time elapsed.”
Dr Maxime Taquet, Associate Professor in the Department of Psychiatry, University of Oxford, said:
“This landmark brain imaging study suggests that the COVID-19 pandemic may have accelerated brain ageing in some people. By comparing scans taken more than two years apart, researchers found that the average person’s brain appeared to age an extra 5.5 months for every year lived during the pandemic. It is important to note that the majority of people showed brain ageing at the expected rate. However, a higher-than-usual proportion showed striking increases in brain age of an extra 15 to 20 months per year.
“Among those infected with COVID-19, the increased brain age correlated with lower scores in a test of thinking skills like attention and problem-solving. This might help explain why some people who had COVID-19 have impaired cognition.
“The findings raise important questions about the long-term neurological impact of the pandemic, whether due to infection itself or the broader psychological and social stress it caused. The authors suggest that the observed brain ageing may reflect a biopsychosocial effect combining the impact of COVID-19 infection with the psychological and social stresses of the pandemic. However, it is also possible that the observed association is primarily biological, driven largely by undetected infections. An analysis by the Institute for Health Metrics and Evaluation estimated that over 90% of the UK population may have been infected by the end of 2022, meaning that many participants classified as ‘uninfected’ might have had asymptomatic or undocumented cases. This raises the possibility that viral exposure played a more central role in the study findings than assumed.
“Another possibility is that the findings do not reflect a causal relationship and are due to a form of selection bias. For instance, if individuals whose brains were ageing more slowly happened to be scanned sooner, and therefore before the pandemic, this could have contributed to the observed association despite the study’s efforts to rule out such confounding.
“The study was well-designed and based on unique UK Biobank data with repeated brain scans. The researchers also acknowledge limitations. The sample excludes people with chronic illnesses such as diabetes and depression and the UK Biobank underrepresents the most socioeconomically deprived groups, the very populations in which the association between the pandemic and brain ageing was largest. This means the association in the general population could be even more pronounced.”
‘Accelerated brain ageing during the COVID19 pandemic’ by Ali-Reza Mohammadi-Nejad et al. was published in Nature Communications at 16:00 UK time on Tuesday 22 July 2025.
DOI: 10.1038/s41467-025-61033-4
Declared interests
Dr Eugene Duff: “I have no conflicts of interest.”
Prof Masud Husain: “I don’t have any conflict of interest.”
Dr Maxime Taquet: “I do not have a conflict of interest.”