Disentangling the neurological impacts of different adversities, such as child neglect and child abuse, shows biological pathways that underpin child development challenges.

Picture children who are having a hard time paying attention and are disrupting a classroom. What’s the best way to address their behavior and help them to concentrate? Is it mindfulness training, to help them calm them down and react less to everything going on around them? Or is it cognitive training to improve their capacity to problem solve, making it easier for them to stick with the learning process, rather than giving up and disrupting their peers? The choice may depend on whether they’ve experienced child neglect or abuse and the impact on their brain development.

Victims of child neglect, or children with few invested caregivers who talk to them and engage them in learning-oriented play, may have a brain that is underdeveloped in areas that support complex thinking. On the other hand, a child who has experienced abuse or violence could have very different biological issues. He or she has a brain that’s been shaped by threat—its biology has been primed to be hypervigilant and overreactive.

These very different biological histories may manifest as what can seem to be the identical problem—disruptive behavior. But if we understand the very different neurological pathways forged variously by child neglect or abuse, we can explain why the same behaviors need different approaches that are tailored to each child’s experiences and neurobiology.

Different treatments for abuse and child neglect

Mindfulness and emotional regulation training could help abused children reduce their emotional reactivity and function better. In contrast, for neglected or deprived children, the answer might be developmentally appropriate, scaffolded learning experiences designed to challenge them. This could even involve, for example, computerised training of their attention skills. Exercises could gradually provide more complex tasks and develop their capacity to think in increasingly difficult ways.

Understanding the neurological impacts of child neglect and abuse 

These scenarios show how neuroscience is providing vital insights into the biological mechanisms, shaped by early experiences, that set in place the pathways to psychological and processing problems. Research is demonstrating how different types of adversity impact brain development in distinct ways. We need to understand these neural mechanisms to develop better targeted, more discriminating and more successful interventions, each designed to address particular brain impacts caused by different kinds of early adversity.

“At least two types of childhood adversity – deprivation (child neglect) and child abuse (threat) – are distinctive in terms of their biological impacts on the human brain.”

Identifying these mechanisms can be challenging, because some children have experienced multiple adversities. However, it is important to disentangle discreet impacts on brain development so that we can design appropriate ways to address them.

Research is making clear that there are at least two types of childhood adversity – child neglect (deprivation) and child abuse (threat) – which have distinctive impacts on the human brain.

Evidence about brain impact of child neglect and deprivation

Deprivation involves an absence of expected inputs from a child’s environment, such as cognitive and social stimulation. It’s a core feature of child neglect and institutionalisation. It can also be found in children with constrained learning opportunities, such as those reared by parents with few opportunities to invest in their children’s development.

We know that animals raised with a lack of environmental stimulation typically experience dramatic increases in synaptic pruning, resulting in reduced cortical volume and thickness in their brains. These changes are accompanied by deficits in learning and memory. The same picture can be found when cognitive enrichment and social stimulation is low during early human development.

child neglect

Photo: David Goehring. Creative Commons.

For example, our studies of children raised in Romanian orphanages, an extreme example of child neglect with severe deprivation of caregiver contact, found that they often had reduced volume and thickness throughout the brain’s cortex. In these orphanages, children were deprived of stimulation, and their young brains developed to become as efficient as possible for the environment they faced. Their brains were learning that they would not need rich synaptic connections for sensory experiences. Our hypothesis is that these synapses would have been “over-pruned”. In brain development, this is a tragic example of the “use it or lose it” principle.

Recent evidence has found similar patterns of brain development, albeit more circumscribed, in children raised in poor households. In such cases, because of a limited social safety net, parents may be working multiple jobs, so they can’t be present with their children and can’t afford high quality care. Thus, their children may also experience some form of child neglect. Other research has identified increased cortical thinning in children from poorer families.

These disruptions to healthy brain development, caused by a lack of cognitive stimulation, underpin reduced capacities to think and learn in such children.

Understanding impact of abuse, living under threat

In contrast, abuse encompasses experiences involving harm or threat of harm. Living with threat is a core feature of sexual abuse, physical abuse and exposure to community violence or war. The biological impact of being raised amid chronic threat is increasingly being documented. It biases the development of cortical and subcortical circuits towards early detection of other threats, and it can create hypervigilance. These biological changes alter emotional development in ways that facilitate the rapid identification of potential threats to the environment, a heightened emotional response to those threats, and a reduced ability to control this response.

“A focus on ‘cumulative risk’ from multiple adversities can fail to distinguish the type, timing or severity of different experiences.”

As a result, children who have experienced physical or sexual abuse are more alert to threatening stimuli. They are more likely to perceive neutral facial expressions as threatening. They also find it difficult to discriminate between threat and safety cues in learning situations. These differences in emotional reactivity and regulation lead to psychological problems such as depression, anxiety and anger-related disorders.

Danger of focus on ‘cumulative’ adversity 

These distinctions between child neglect/deprivation and child abuse/threat have been ignored in recent research focused on “cumulative risk”. Cumulative risk focuses on children experiencing multiple adversities. This approach rightly recognises a key reality—children exposed, for example, to poverty, deprivation and child neglect are also more likely to experience violence and abuse. The multiplicity of adversity is, in itself, dangerous to children. However, this cumulative approach, which is dominant in the field, can fail to distinguish the type, timing or severity of different experiences. It also throws little light on the different mechanisms by which children’s psychopathology is impacted and makes it harder to design interventions to address the psychological problems which result from adversity exposure.

Neglect in Romanian orphanages

Our research into the children raised in Romanian orphanages is pertinent. They suffered severe child neglect, deprived of both attachment and stimulation. We were able to show that exposure to institutionalization early in life caused clear reductions in IQ and cognitive function, and changed their neural structure.

Our work – comparing the brains of infants rescued early with those who remained institutionalised for longer – has also helped us understand how these losses may be recoverable. Children who moved into families before they were two years old were able to recover in some ways with regards to their stress responses and IQ. This was less true for their executive functioning and attention – recovering this capacity seems to require even earlier intervention. Some research suggests that children who were rescued before they were six months old were doing a lot better in terms of executive function.

Adolescence is an important intervention opportunity

Neuroscience is helping practitioners understand when—and in response to which experiences—the brain is more plastic, making it responsive to certain interventions. We know that the brain remains plastic throughout life, but much less so after infancy, and plasticity apparently declines with age. But current research suggests that there may be another opportunity for plasticity during adolescence.

Linda Wilbrecht at the University of California, Berkeley (see https://wilbrecht.org/) has shown that hormonal changes at this age increase brain plasticity. This finding offers the intriguing and hopeful possibility that interventions around adolescence – ensuring that children experience positive relationships with trusted caregivers – may offer a second major opportunity, beyond infancy, to recover from child neglect or abuse, making a great difference in children’s brain development and their lifetime prospects.

Header photo: Christophe Laurent. Creative Commons. 

References

 Miller AB, Sheridan MA, Hanson JL, McLaughlin KA, Bates JE, Lansford JE, Pettit GS & Dodge KA (2018), Dimensions of deprivation and threat, psychopathology and potential mediators: A multi-year longitudinal analysis, Journal of Abnormal Psychology 127.2

 Sheridan MA & McLaughlin KA (2014), Dimensions of early experience and nueral development: Deprivation and threat, Trends in Cognitive Sciences 18.11

 McLaughlin KA, Sheridan MA & Lambert HK (2014), Childhood adversity and neural development: Deprivation and threat as distinct dimensions of early experience, Neuroscience and Behavioral Reviews 47