Severe childhood deprivation may cause long-term changes to the size and structure of the brain, according to new research.
Scientists found the brains of Romanian young adults who were institutionalised and experienced childhood neglect in their home country were around 8.6 per cent smaller than those of their English counterparts who did not suffer childhood deprivation.
The team, which included researchers from King’s College London, also found that longer time spent neglected in orphanages was associated with a smaller total brain volume.
The study, published in the journal Proceedings Of The National Academy of Sciences, is the first to investigate the impacts of severe early childhood deprivation on the brain structure of young adults.
The research is part of an ongoing scientific project which started running in 1990 called the English and Romanian Adoptees (ERA), involving a random sample of children from Romania and England who were later adopted.
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The Romanian participants in the study had suffered severe childhood deprivation, were often malnourished and had minimal social contact and little stimulation before being adopted into nurturing families in the UK.
Previous research involving the same cohort has linked mental health, low IQ and greater attention deficit hyperactivity disorder (ADHD) symptoms with childhood deprivation.
How was this study carried out?
In the most recent study, researchers analysed brain scans of 67 participants from the Romanian group, aged 23 to 28. They then compared these brain scans to those of 21 English adoptees of a similar age range.
The team found that the longer the time the Romanian adoptees spent in the institutions, the smaller the total brain volume, with each additional month of deprivation associated with a 0.27 per cent reduction in total brain volume.
Statistical analysis showed that changes in brain volume related to deprivation were also associated with ADHD symptoms and lower IQ in the Romanian adults.
The researchers also found that the young Romanian adults had “markedly smaller right inferior frontal regions of the brain both in terms of volume and surface area”, compared to the UK adoptees. In contrast, the brain’s right inferior temporal lobe was larger in volume and surface area and thickness for the Romanian young adults, which the researchers said was associated with lower levels of ADHD symptoms.
Growing up poor can affect your DNA as well as your health
Professor Thomas McDade explains how the process of ‘DNA methylation’ can change the very structure of your genes.
We’ve known for a long time that individuals who have a lower level of socioeconomic status suffer from worse health throughout their lives. They die earlier, they are at increased risk of cardiovascular diseases, metabolic diseases, infectious diseases – basically everything on the social gradient of health.
But it’s been a bit of a mystery how that happens. How is it that our bodies in a sense remember the experiences that we have had growing up? And how do those experiences – in this case experiences associated with socioeconomic status – affect cellular function and physiology with implications for health?
We found that lower levels of socioeconomic status were associated with DNA methylation on a large number of sites across a large number of genes – more than 1,500. To me, this was somewhat surprising.
We are showing that socioeconomic status touches nearly 10 per cent of the genes in our bodies and has the potential to affect their structure and function.
This implies that the increase in volume and surface area in this region may play a compensatory role in preventing development of ADHD symptoms, the researchers added.
Professor Mitul Mehta, from King’s College London’s Centre for Neuroimaging Sciences and neuroimaging lead for the study, said: “We found structural differences between the two groups in three regions of the brain.
“These regions are linked to functions such as organisation, motivation, integration of information and memory.
“It’s interesting to see the right inferior temporal lobe is in fact larger in the Romanian young adults and that this was related to fewer ADHD symptoms, suggesting that the brain can adapt to reduce the negative effects of deprivation.”