Jan. 6 (UPI) -- Those who experience trauma and extreme poverty in childhood may lag behind others in terms of brain development, resulting in intellectual and behavioral difficulties as adults, a new study suggests.
In an article published Monday in the Proceedings of the National Academy of Sciences, researchers from King's College London show that the brains of young adult Romanian adoptees who were institutionalized as children are nearly 9 percent smaller than those of English adoptees. These changes in brain volume were associated with lower IQ and more symptoms of attention-deficit hyperactivity disorder, the authors report.
"This study addresses one of the most fundamental questions in developmental psychology and psychiatry," Edmund Sonuga-Barke, a professor of developmental psychology, psychiatry and neuroscience at King's College and a study co-author, told UPI. "How does early experience shape individual development? Do bad experiences make an indelible mark on a person which alters their life in fundamental ways or can these be overcome if good experiences follow later?"
Sonuga-Barke and his colleagues analyzed the MRI brain scans of 67 young adults between 23 and 28 years of age who were exposed to "severely depriving conditions" in Romanian institutions under the Communist regime, and subsequently adopted into "nurturing families" in Britain.
The researchers compared their scans to those of 21 English adoptees, between 23 and 26 years of age, who had not suffered this institutional deprivation.
According to the researchers, the Romanian study subjects had been admitted into institutions in the eastern European nation in the first few weeks of their lives. While in these facilities, they were often malnourished, had minimal social contact and engaged in few activities.
Study subjects spent anywhere from three months to four years spent in the institutions prior to adoption into families in the Britain.
In general, the authors identified structural differences between the two groups of participants in three regions of the brain linked to functions such as organization, motivation, integration of information and memory.
Statistical analysis performed by the authors showed that changes in brain volume among the Romanian study participants were associated with lower IQ and more ADHD symptoms, suggesting that changes in brain structure could play a role between the experience of deprivation and levels of cognitive performance and mental health.
For example, in comparison to the English adoptees, the young Romanian adults had markedly smaller right inferior frontal regions of the brain both in terms of volume and surface area. In contrast, the right inferior temporal lobe was larger in volume, surface area and thickness.
This latter difference was associated with lower levels of ADHD symptoms. The authors believe the increase in volume and surface area in this region may play a compensatory role in preventing development of ADHD symptoms.
In the right medial prefrontal region, the longer the duration of deprivation, the larger the volume and surface area, they added, suggesting that the human brain can adapt to reduce the negative effects of deprivation, which may explain why some individuals appear less affected than others.
The researchers investigated other possible factors that could have influenced the results but found they were unaffected by level of nutrition, physical growth and genetic predispositions.
The PNAS study was performed as part of the ongoing English and Romanian Adoptees Brain Imaging Study, which has collected information from adoptees from both countries over time, including measures of mental health and cognitive performance.
"Our previous research has shown that the individuals were severely affected when they first arrived in their adoptive homes but that many recovered a great deal," Sonuga-Barke said. "However, for many, very significant problems in cognition and social behavior have persisted right through to adulthood. Such effects were limited to adoptees who experienced extended deprivation. They are also increasingly affected by emotional problems. The persistence of these problems across the life span despite a long period of post-adoption environmental enrichment clearly suggested that they were likely caused by fundamental alterations in brain processes occurring early in life."