Scientists have linked the impact of living in an unequal society to structural changes in the brains of children – regardless of individual wealth – for the first time.
A study of more than 10,000 young people in the US discovered altered brain development in children from wealthy and lower-income families in areas with higher rates of inequality, which were also associated with poorer mental health.
The data was gathered from the Adolescent Brain Cognitive Development study and published in the journal Nature Mental Health.
Researchers at King’s College London, Harvard University, and the University of York then measured inequality within a particular US state by scoring how evenly income is measured. States with higher levels of inequality included New York, Connecticut, California and Florida, while Utah, Wisconsin, Minnesota and Vermont were more equal.
MRI scans were analysed to study the surface area and thickness of regions in the cortex, including those involved in higher cognitive functions including memory, emotion, attention and language. Connections between different regions of the brain were also analysed by the scans, where changes in blood flow indicate brain activity.
The research found that children living in areas with higher levels of societal inequality, including socioeconomic imbalances and deprivation for example, were linked to having a reduced surface area of the brain’s cortex, and altered connections between multiple regions of the brain.
The findings, the first to reveal the impact societal inequality has on the structures of the brain, also provided evidence that the impacted neurodevelopment might relate to future mental health and cognitive function. Notably, these brain changes in children were seen regardless of their economic background.
Dr Divyangana Rakesh, at the Institute of Psychiatry, Psychology and Neuroscience, King’s College London, said the study was not about individual family income but how income was distributed in society.
“Both children from wealthy and lower-income families showed altered neurodevelopment, and we established that this has a lasting impact on wellbeing. We are interested to see how these findings compare around the world,” she said.
“For example, several areas in the UK are characterised by high income inequality. London exhibits significant inequality, with both very rich and very poor residents. Future research could examine income inequality in the UK at the level of counties and boroughs to investigate whether similar effects are observed.”
The researchers also analysed data from questionnaires taken by the children, with the aim of revealing mental health conditions such as depression and anxiety, at ages 10 and 11, six and 18 months after the MRI scans.
Mental health outcomes were significantly worse for those who lived in societies with higher levels of wealth inequality. Furthermore, some of the structural changes observed in the children’s brains were linked to functional alterations, which were in turn associated with worse mental health.
Prof Vikram Patel of Harvard, a co-author of the study, said the findings added to the “growing literature which demonstrates how social factors, in this instance income inequality, can influence wellbeing through pathways which include structural changes in the brain”.
Prof Kate Pickett of the University of York, another co-author of the study, said: “Our paper emphasises that reducing inequality isn’t just about economics – it’s a public health imperative.
“The brain changes we observed in regions involved in emotion regulation and attention suggest that inequality creates a toxic social environment that literally shapes how young minds develop, with consequences for mental health and impacts that can last a lifetime.
“This is a significant advance in understanding how societal-level inequality gets under the skin to affect mental health.”
The study was funded by the Brain and Behaviour Research Foundation, the UKRI Medical Research Council and the National Institute of Mental Health.
