The Neurobiology behind Child Abuse and Neglect

Content Warning: Mentions of Child Abuse and Neglect

We often hear parenting is an art and that parents should be cautious about how they raise their children. What happens when parents do not do so? Children seek therapy.

Since we are familiar with how therapy helps to deal with childhood trauma and abuse, I would like to discuss a niche in parental neglect not often considered in everyday life. That is the neurobiological changes that occur with respect to anatomy, hormones and metabolic reactions that are brought about during child neglect and abuse.

Of all forms of child maltreatment, child neglect is the most common one. Nearly 700,000 children are recorded as having experienced child maltreatment in the United States each year, with neglect accounting for about 60% of those cases. Even though it is highly prevalent, this form is not studied often. Mainly the reasons could be because there is no standard classification for grading the severity of parental neglect. Sometimes it could be falsely reported as well. Surprisingly, data from the United States reveals that the biological mother is the most common offender of child neglect, with maternally committed neglect being documented in approximately 80% of confirmed cases.

The following were the neurobiological changes observed as a consequence of parental neglect and abuse

1. Changes in the anatomical structures

• Hippocampus: The hippocampus is arguably the most obvious place in the brain to look for signs of possible child abuse. It is especially vulnerable to harm from excessive doses of glucocorticoids, such as cortisol, due to its dense population of glucocorticoid receptors. Many studies have reported that adults who endured childhood maltreatment had decreased hippocampus size which shows that this region was exposed to high levels of glucocorticoid.

• The Orbitofrontal cortex (OFC): OFC is a region in the brain responsible for early social regulation and learning. This was found to be reduced in volume among children exposed to abuse and neglect.

• Amygdala: Another region which was seen to be affected in children who had undergone parental neglect and abuse. This region of the brain is responsible for fear conditioning and emotional processing. Studies which investigated the effects of stress caused by parental neglect found that the amygdala volume had increased compared to normal levels. This could be due to the atypical development of limbic circuitry.

2. Hormonal changes

Two hormones majorly studied in the aspect of childhood neglect are oxytocin and dopamine.

a) Oxytocin

Neglected maternal behaviour may have a negative effect on the development of the oxytocin system in female offspring. Studies in rodents showed varied oxytocin receptor expression due to natural changes in rodent pup licking and grooming. This could thus influence the levels of oxytocin produced. Oxytocin is required for social recognition and knockout studies with respect to this hormone in mice showed reduced social memory. This proves that oxytocin is very important for future unimpaired maternal behaviour of female offspring.

b) Dopamine

Dopamine is an essential neurotransmitter required for maternal caregiving, motivation and memory. This was proven by researchers who introduced pharmacologic antagonists of dopamine D1 receptors into mice, so dopamine was not supplied in required quantities to the cells. Dopamine knockout studies in mice also proved the same.

When mice pups were separated from their mother to simulate an environment of neglect, the pups showed elevated levels of dopamine which led to acute stress.

The mice pups were also highly sensitive to psychostimulants like cocaine which are dopaminergic neuron activators. This also explains why kids experiencing parental neglect are susceptible to drug addiction.

A simple, low-risk, affordable pharmaceutical intervention to improve mother-infant bonding may be provided by research on these topics, which could have practical consequences for the final treatment of maternal neglect. It could also help in creating novel, pharmaceutical treatments to assist behavioural and psychosocial therapy because maternal neglect is a significant public health issue with detrimental long-term effects on child development and behaviour.