Childhood maltreatment can continue to have an impact long into adulthood because of how it effects an individual’s risk of poor physical health and traumatic experiences many years later.
This is according to a study – “Childhood maltreatment influences adult brain structure through its effects on immune, metabolic, and psychosocial factors” by Sofia C. Orellana, Richard A. I. Bethlehem, Ivan L. Simpson-Kent, and Edward T. Bullmore – that appeared in the Proceedings of the National Academy of Sciences.
According to the researchers, individuals who experienced maltreatment in childhood – such as emotional, physical and sexual abuse, or emotional and physical neglect – are more likely to develop mental illness throughout their entire life, but it is not yet well understood why this risk persists many decades after maltreatment first took place.
In this study, the researchers examined MRI brain scans from approximately 21,000 adult participants aged 40 to 70 years in UK Biobank, as well as information on body mass index (an indicator of metabolic health), CRP (a blood marker of inflammation) and experiences of childhood maltreatment and adult trauma.
The researchers found that adult brains continue to be affected by childhood maltreatment in adulthood because these experiences make individuals more likely to experience obesity, inflammation and traumatic events, all of which are risk factors for poor health and wellbeing, which in turn also affect brain structure and therefore brain health.
Orellana, a PhD student at the Department of Psychiatry and Darwin College, University of Cambridge, said: “We’ve known for some time that people who experience abuse or neglect as a child can continue to experience mental health problems long into adulthood and that their experiences can also cause long term problems for the brain, the immune system and the metabolic system, which ultimately controls the health of your heart or your propensity to diabetes for instance. What hasn’t been clear is how all these effects interact or reinforce each other.”
Using a type of statistical modelling that allowed them to determine how these interactions work, the researchers confirmed that experiencing childhood maltreatment made individuals more likely to have an increased body mass index (or obesity) and experience greater rates of trauma in adulthood. Individuals with a history of maltreatment tended to show signs of dysfunction in their immune systems, and the researchers showed that this dysfunction is the product of obesity and repeated exposure to traumatic events.
Next, the researchers expanded their models to include MRI measures of the adult’s brains and were able to show that widespread increases and decreases in brain thickness and volume associated with greater body mass index, inflammation and trauma were attributable to childhood maltreatment having made these factors more likely in the first place. These changes in brain structure likely mean that some form of physical damage is occurring to brain cells, affecting how they work and function.
Professor Bullmore from the Department of Psychiatry and an Honorary Fellow at Downing College, Cambridge, said: “Now that we have a better understanding of why childhood maltreatment has long term effects, we can potentially look for biomarkers – biological red flags – that indicate whether an individual is at increased risk of continuing problems. This could help us target early on those who most need help, and hopefully aid them in breaking this chain of ill health.”
