The effects were more pronounced in children who stayed longer in neglected conditions. Every additional month of deprivation was linked to a 0.27% reduction in total brain size, says the study. Smaller brain size due to deprivation may mess with brain development: neglected children tend to have a lower IQ and more symptoms of attention deficit hyperactivity disorder (ADHD), say researchers.
The study was conducted on children adopted from Romanian orphanages by UK families in the early 90s. These children had endured violence, neglect and malnourishment. Many of them are still carrying the scars of the past: previous research has shown that many are still experiencing mental health problems even in adulthood, despite being brought up by caring new families.
“The English and Romanian Adoptees (ERA) study addresses one of the most fundamental questions in developmental psychology and psychiatry — how does early experience shape individual development? It is essential to recognize that these young people have nearly always received great care in loving adoptive families since they left the institutions. However, despite a lot of positive experiences and achievements there remain some deep-seated effects of deprivation on these young adults,” says the principal investigator of the study, Dr. Edmund Sonuga-Barke from the Institute of Psychiatry, Psychology & Neuroscience (IoPPN), King’s College London.
“Previous research on the ERA study has suggested that the emergence and persistence of low IQ and a high level of ADHD symptoms involves structural changes in the brain but, until now, we have not been able to provide direct evidence of this,” says Dr. Nuria Mackes from IoPPN, the first author of the study.
In order to provide concrete evidence, the team set up an experiment to examine the impacts of severe early childhood deprivation on the brain structure of young adults. First, the scientists took MRI brain scans of 67 young Romanian adults, aged 23-28 years, who entered into institutions in the first few weeks of life. They spent anywhere between three and 41 months at the institutions, before being adopted by families in the UK. Then, the team compared the brain scans of these 67 adults with MRI scans of 21 English adoptees, aged 23-26 years who had not suffered this institutional deprivation.
The team ruled out other factors that could interfere with the results of the experiment such as the level of nutrition, physical growth and genetic predisposition for smaller brains.
The Romanian adults showed differences in some portions of their brains. “We found structural differences between the two groups in three regions of the brain. These regions are linked to functions such as organization, motivation, integration of information and memory,” says Dr. Mitul Mehta from the IoPPN, one of the authors of the study.
Their findings also explain why some Romanian adults show resilience to deprivation during early childhood: one in five of them remained unaffected. This, according to Mehta, may be explained by a brain structure called the right inferior temporal lobe. “It is 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. This may explain why some individuals appear less affected than others by deprivation.”
These results, according to the team, could pave the way for support and care for neglected individuals, transitioning into adulthood. Targeting the right inferior temporal lobe area directly through training might reduce ADHD symptoms, says Dr Sonuga-Barke.
The study was published in Proceedings of the National Academy of Sciences.