The Effect of Childhood Adversity on the Adult Brain

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We all have been acquainted with the term ‘childhood trauma’ – referring to the experience of an event that transpired during childhood, that causes significant amount of distress and can, in many cases, result in lasting emotional or physical effects.

We often associate trauma when we discuss long-term effects on child development. Interestingly, however, there has been recent literature suggesting that alongside the effects of trauma, there are some other forms of experiences that a child can have that could leave a permanent and persistent mark on their development.

‘Childhood adversity’ is a term coined to refer to a range of circumstances and events which can severely damage a child’s physical or psychological wellbeing. There are three major types of Adverse Childhood Experiences (ACEs): abuse, neglect and household dysfunction.

The limbic system structures: the hypothalamus, the thalamus, the amygdala, the hippocampus and their (primary) functions.

Childhood adversity is an established risk factor for Major Depression Disorder (MDD) in adulthood. It can trigger biological changes in brain structures, that could lead to maladaptive functioning when faced with stressful situations, increasing the risk of psychiatric disorders. There are many resources that purport the effect of MDD on the brain, particularly in two structures of the limbic system: the hippocampus and the amygdala.

In the hippocampus, the association is clear; individuals with MDD often show a reduced volume of the hippocampus. In the amygdala, however, the reports of difference in volume have been inconsistent.

In a recent study at the University of Alberta, researchers examined the associations between amygdala and hippocampal regions, and any history of childhood maltreatment in individuals with MDD. For this study, MRI scans were taken of the brains of 35 patients diagnosed with MDD and 35 healthy controls.

Manually, the amygdala and the hippocampal areas were delineated and measured. Childhood maltreatment was measured using the Childhood Trauma Questionnaire.

“Understanding the specific structural and neurochemical brain changes that underlie mental health disorders is a crucial step towards developing potential new treatments for these conditions, which have only increased since the onset of the COVID-19 pandemic,” remarked one of the researchers.

The findings did not disappoint; in participants with MDD, a history of maltreatment had a significant negative association with volume in the right amygdala, anterior hippocampus and total cornu ammonis subfield bilaterally; all medial temporal lobe structures.

The findings of this study shed light on the neurological changes that come to be in the brain of an adult suffering from MDD, following childhood maltreatment.

“This study provides in vivo evidence that childhood adversity might have negative effects on specific brain subregions in participants with MDD, namely the basolateral amygdala and the CA1–3 hippocampal subfield”, conclude the researchers.

Interestingly, the researchers were also curious about how the findings would complement research into novel treatment for MDD, such as psychedelics; which are increasingly evidenced to have abilities of nerve regrowth for the investigated areas.

Being able to pinpoint the specific sub-regions of the amygdala or the hippocampus that are altered by these incidents helps us find useful mechanisms to prevent or reverse these effects. It also helps identify ways in which maltreatment leads to mental health disorders.

Relevant Sources:

Original Source:
Sereshki, A. A., Coupland, N., Silverstone, P., Hegadoren, K., Carter, R., & Malykhin, N. (2021). Effects of Childhood Adversity on the Volumes of the Amygdala Subnuclei and Hippocampal Subfields in Major Depressive Disorder: High-Field Magnetic Resonance Imaging Study. Biological Psychiatry87(9). https://doi.org/10.1016/j.biopsych.2020.02.993

Article Link: http://jpn.ca/46-1-e186/

Image: by Pixabay from Pexels

Edited by Malavika Ramanand

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