Disadvantage and brain development: flags for GPs

NUMEROUS studies of children over decades have found startling connections between low socio-economic status (SES) and poor physical, educational and mental health outcomes.

For example, studies from Australia and other countries (here and here) show that poverty has a negative effect on learning and educational performance. According to the research, children who grow up in poverty have slower cognitive development and lower IQs, with the latter effect being more noticeable in children who were exposed to poverty early in life. It is possible these differences arise due to trauma, lower cognitive stimulation, lower quality of medical treatment and nutrition, greater exposure to psychological stress, and environmental contaminants, all of which can have a detrimental effect on children’s development.

Further, there is mounting evidence that quantifiable links between SES and changes in brain structure and function may serve as mechanisms that transmit the effects of low SES on child development.

Importantly, however, SES is a broad construct and can be measured in different ways (eg, parent education, income) and at the family or neighborhood level. While related, each measure may represent distinct risk factors.

For example, low parent educational attainment may impact child development via lower cognitive stimulation in the home, whereas more socio-economically disadvantaged neighborhoods may affect children via greater exposure to toxicants, pollutants, noise, and peer influences.

As such, we set out to investigate and understand the independent effects of these SES indicators on child brain development. In addition, we also examined whether high SES in one domain is able to buffer the effects of low SES in another. This knowledge could help identify which children are most at risk

In our latest research, published on 18 August 2022 in JAMA Network Open, a large sample of almost 9000 children aged 9–10 years from the Adolescent Brain Cognitive Development Study from the US, found that children living in more disadvantaged neighbourhoods had widespread reductions in cortical thickness, particularly in brain regions supporting cognitive functioning and sensorimotor processing. However, we found that this was only the case when children lived in households with low incomes. That is, living in a household with a high income mitigated the effects of low neighborhood SES on the brain. Income similarly mitigated the adverse effects of low parental educational attainment on the brain. These findings suggest that programs aimed at reducing poverty (eg, through cash transfers, voucher programs) may be beneficial in mitigating some of the negative effects of low education or neighborhood disadvantage on children’s brain development.

Flags for GPs

Our findings suggest that neighborhood disadvantage is a potent predictor of brain health. As such, clinicians could focus on children living in poor neighborhoods and assess their mental health and cognitive development. Further, children from homes where parents have low educational attainment and income are also at risk for brain alterations. Clinicians may be able to spot children that require special attention using the snapshot provided by Harding and Szukalska. For example, the average dependent child living in poverty in Australia may live in a family with a sole parent or where the head of the household is unemployed, have one or both parents who are self-employed or involved in part-time work, and have two or more siblings. Clinicians can also easily obtain information on the level of neighbourhood disadvantage for a child via tools available on the Australian Bureau of Statistics website.

Children who meet some of these criteria could be assessed for mental health and behavioural issues using a questionnaire such as the Strength and Difficulties Questionnaire, and referred for additional assistance if needed.

Available interventions and preventing long term harm

To lessen the effects of poverty, welfare agencies during the past 10 years have built family support and early intervention programs in addition to providing urgent aid to children in need. According to Mission Australia, there are over 10 000 such initiatives (Chapter 11.84). Early intervention has also gained ground at the state and federal levels. Examples include the Families First Strategy in New South Wales, the Together strategy in Tasmania (Chapter 11.84), the Victorian Government’s Best Start Strategy, and the Commonwealth’s Stronger Families and Communities Strategy. However, there are very few interventions that include neurobiological measurements, and we are not sure about how effective these interventions are at mitigating the effects of low SES on brain structure and function.

Work by us and others (here, here, here and here) has shown that environmental factors, such as better home and school environments, can buffer some of the negative effects of neighbourhood disadvantage on the brain. Within communities plagued by poverty, good parenting practices represent an incredibly significant resource. To safeguard infant and child development in socio-economically disadvantaged communities, we should focus on how to maintain, strengthen, and extend this care.

Interventions designed to improve the parent–child relationships range from self-guided online programs to live coaching during parent–child interactions, to home visits. Examples include Triple P, Tuning in to Kids, and Partners in Parenting. These interventions have the goal of improving emotional connection in the parent–child dyad and also educating caregivers on how to set boundaries while remaining loving and warm.

When doctors and other health practitioners encounter parents from socio-economically disadvantaged backgrounds, they could highlight the importance of caregiving as a key mechanism that can help their children flourish, and refer them to such initiatives. In addition, on the point of caregiving, given that financial adversity can impact parent mental health, which can in turn have a negative effect on parenting practices, brain health and child outcomes, doctors could also assess disadvantaged parents’ mental health and support their wellbeing and stress management.

This is particularly important for parents with young children. While adolescence is a very important developmental period, to prevent long-term harm, attention also needs to be paid to the early years when the brain is rapidly developing. Indeed, the brain is most dynamically developing in the first few years of life, so SES during this time is likely to have the most substantial and long-lasting effects on child outcomes.

Dr Divyangana Rakesh is a Postdoc at Harvard University, after completing her PhD at the Melbourne Neuropsychiatry Centre at the University of Melbourne.

Professor Sarah Whittle is a Principal Research Fellow and Head of the Affective Neurodevelopment Research Stream at the Melbourne Neuropsychiatry Centre, University of Melbourne and Melbourne Health.

Andrew Zalesky is Associate Professor and Principal Researcher at the University of Melbourne. He holds a joint appointment between the Faculties of Engineering and Medicine.

The statements or opinions expressed in this article reflect the views of the authors and do not necessarily represent the official policy of the AMA, the MJA or InSight+ unless so stated.

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