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.
The 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 findings suggest “inequality creates a toxic social environment” that “literally shapes how young minds develop”, researchers said.
Experts from King’s College London (KCL), the University of York and Harvard University looked at MRI scan images from 10,071 children aged nine and 10 in 17 US states who were involved in the Adolescent Brain Cognitive Development (ABCD) study.
The team measured inequality by scoring how evenly income is measured in society. States with higher rates included New York, Connecticut, California and Florida, while Utah, Wisconsin, Minnesota and Vermont had narrower income gaps.
Using scan images, researchers studied the surface area and thickness of regions of the cortex – the wrinkly outer layer of the brain – including the areas used for memory, attention, emotion and language. They also looked at links between different regions of the brain and changes in blood flow that showed brain activity.
The study found that children living in areas with higher rates of inequality had a reduced cortex surface area and altered connections between different areas of the brain, regardless of individual circumstances such as family income and education.
Experts said the findings, published in Nature Mental Health, showed income inequality was “a unique societal-level determinant of neurodevelopment and mental health, independent of individual socioeconomic status”.
Dr Divyangana Rakesh, of the Institute of Psychiatry, Psychology and Neuroscience at KCL, said: “This isn’t just about individual family income, it is about how income is 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.”
Researchers also explored how these changes in the brain might impact on mental health. The team used data from questionnaires taken when the children were 10 and 11 and found mental health was worse for those who lived in unequal societies.
Prof Kate Pickett, a co-author of the study from the University of York, said the findings showed reducing inequalities “isn’t just about economics – it’s a public health imperative”.
She said: “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.”
Rakesh said: “Progressive taxation, increased social safety nets and universal healthcare could help alleviate the stressors that disproportionately affect children in more unequal societies. Community-building initiatives and investments in public infrastructure could also mitigate the detrimental effects of inequality by promoting trust and social cohesion.”
Future studies could focus on inequalities in the UK, Rakesh said. “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.”
