Deprivation’s Mark on the Brain
IN 2000, professor of pediatrics Charles Nelson went on a trip that would change the course of his life—and the lives of dozens of others. As an expert in developmental neuroscience, Nelson was accompanying two colleagues on a visit to St. Catherine’s Orphanage in Bucharest, Romania, which was part of a network of state-run orphanages established by the former dictator Nicolae Ceaușescu. A series of disastrous policy decisions by Ceaușescu had resulted in more than 170,000 Romanian children being abandoned to these institutions throughout the 1980s, where they were victims of severe neglect.
By the time Nelson arrived, Ceaușescu had been out of power for more than a decade, but the situation in the orphanages remained dire. One of Nelson’s colleagues who ran an international adoption clinic had noted that many children reared in such institutions developed neurodevelopmental problems, including attention deficit hyperactivity disorder (ADHD), autism, and a host of pathological behaviors; these observations matched Nelson’s own impressions on meeting young orphans in Bucharest. He and his colleagues wanted to know why institutional rearing so often led to disability and psychopathology.
His visit marked the beginning of the Bucharest Early Intervention Project (BEIP), a first-of-its-kind study on the long-term effects of psychosocial deprivation on children raised in institutions. When Nelson and his colleagues originally established the project, they enrolled 136 institutionalized Romanian children whose average age was 20 months and randomly assigned them to remain in the institution or be adopted by a foster family. They also enrolled 72 children who had never been in an institution as a control group. For the past 22 years, he and his colleagues have followed the lives of these Romanian orphans to understand how their early experience affected their subsequent neurocognitive development. The research, described in more than 100 papers and a book, traces the profoundly negative effects of psychosocial deprivation on both behavioral and brain development.
The project’s most recent research revealed that children who were removed from the institutions and raised in foster homes exhibited faster and more dramatic paring of brain matter in the prefrontal cortex from age 8 to age 16 than children who remained in the institutions.
Among children who grew up in these orphanages, “The regions of the brain where changes were most pronounced are regions that are involved in higher order social and cognitive abilities, which help explain increases in things like ADHD,” says professor of psychology Katie McLaughlin. “These findings show that far and away the best thing we can do to support healthy brain development, and development across other domains, is to ensure that children have access to stable caregiving.”
The fact that early psychosocial deprivation affects the physical development of the prefrontal cortex is significant because this region is responsible for many higher cognitive processes, including the ability to plan, inhibit inappropriate thoughts and behavior, and hold information in short-term memory. The prefrontal cortex is one of the last areas of the brain to fully develop; the gray matter in this brain region is typically “pruned” through adolescence among children raised in healthy family environments.
This pruning is a phenomenon well known in neuroscience. In general, synapses and circuits in the brain are pruned based on experience, which leads to selection of a subset that is confirmed and stabilized while other neural circuits fall away. For example, adults can easily discriminate between two faces in a fraction of a second because the streamlined connections in their prefrontal cortex enable more efficient processing of such distinctions. Babies take much longer because they must respond to input from an abundance of synapses. As revealed in the recent BEIP study, the pruning of connections in the prefrontal cortex is driven in part by psychosocial input, including sensitivity and responsiveness, from caregivers.
“The children in the institutional group actually have a thicker cortex, which is bad because it means they haven’t pruned away these extraneous connections,” says Nelson. Importantly, this thickening became evident when the children were only a few years old. When their brains were imaged again at age 16, they still had thicker cortices, suggesting that their very early experiences have a major impact on their young adult outcomes. “That’s sobering because it means if we want children who grow up in deprived environments to recover,” he says, “they need to be removed from those environments at a very young age.”
This study is not the first to link childhood deprivation to structural changes in the brain. But almost all the data in previous research came from animal models or were based only on studies of institutionalized children fortunate enough to be adopted. The BEIP study is the first to demonstrate this finding in a randomized controlled trial, with cohorts differing in the duration of their institutionalization. That enabled the researchers to make a causal inference linking psychosocial deprivation to structural brain changes that are associated with neurocognitive disabilities.
In most countries this kind of study wouldn’t be considered ethical. But the Romanian government had no foster care system due to concerns about child trafficking and other forms of exploitation, which meant that Nelson and his colleagues had to build a foster system from scratch to run the study. That any children would be adopted through the foster care network they established was therefore a net benefit.
One of the “really positive” outcomes of this research is that it is now “illegal in Romania to institutionalize young children,” says McLaughlin, who co-led the most recent study with Margaret Sheridan, a professor of psychology at the University of North Carolina-Chapel Hill (both have been involved with the project since 2008, when they were postdoctoral researchers in Nelson’s lab). “Romania now has a foster care system much like the foster care system in the U.S., and these huge institutions for children no longer exist.”
During the past two decades, the BEIP has conducted follow-up studies on the orphans every four years. This longitudinal research has confirmed the continuing negative impact that early deprivation has on the children’s development. And it suggests that the earlier they are removed from institutions and placed in foster care the better; notably, removing children from institutions before the age of two seems to be particularly critical for healthy development. Although children placed in foster care before the age of two are still at a disadvantage compared to children who have never been in an institution, they will have remarkably better outcomes than children who spend their entire early childhood deprived of nurturing caregiving.
How much caregiving is needed to optimize childhood development remains unknown, as is the deprivation threshold that leads to impaired development. But the existing evidence has important policy implications. Millions of children are being raised in institutions around the world, including tens of thousands in the United States. Tens of thousands more American children experience neglect outside of institutions—in dysfunctional families.
“Institutionalization is an extreme on the continuum of deprivation that drives these developmental differences,” says McLaughlin, “and child neglect is its next-door neighbor. The evidence could not be more clear that placement into a supportive family is by far the best thing we can do for those children, and figuring out strategies to make foster care more accessible is critically important.”