Team Investigates Links Between Childhood Exposure to Violence, Biomarkers and Behavioral Outcomes
By Erin Frick
ALBANY, N.Y. (Nov. 17, 2022) — A team of interdisciplinary University at Albany researchers from the Departments of Psychology, Sociology and Epidemiology & Biostatistics have published a new study that surveyed the landscape of research into biomarkers associated with childhood exposure to violence and negative behavioral outcomes later in life.
The work is part of a broader research effort led by Melissa Tracy, associate professor at UAlbany’s School of Public Health, to understand the biological, social and environmental determinants of violent behavior and how violence is transferred through families and communities.
“All aspects of our biology, environment and life experiences have the potential to influence how we learn to perceive the world and respond to different situations,” said Tracy, senior author on the study. “Since these many interacting factors occur together, it is critical that we understand how different combinations of experiences influence other co-occurring factors, as well as outcomes later in life.”
A biomarker is a measurable indicator of a biological state such as heart rate, blood pressure and hormone levels. Biomarkers associated with stress influence how we feel and act. Interacting with other social and environmental factors, our biology shapes our behavior.
Childhood exposure to violence has been linked to “externalizing behaviors” which include things like aggression and delinquency. These behaviors put individuals at greater risk of experiencing problems with employment, socialization, mental disorders and crime. Understanding the factors that influence these outcomes, including the ways that childhood experiences “get under the skin” to influence certain behaviors, can inform strategies for diagnosis and early interventions.
Surveying the Research Landscape
In this study, the team undertook a systematic review of existing research looking at the associations between childhood exposure to violence, biomarkers and externalizing behaviors.
After collecting and screening 3,878 studies of potential relevance, they narrowed their pool down to 44 papers that met their criteria for inclusion. Types of exposures included categories like child abuse, community violence, harsh parenting and marital conflict. Biomarkers included things like cortisol levels, cardiac signals and perspiration. Externalizing behaviors included physical aggression, dating conflict, antisocial behavior and delinquency, among others.
The team reviewed the findings from each study and brought them together to assess what associations have been measured, what do we know, what gaps need to be addressed and how can we best fill them?
Overall, results linking different types of childhood violence exposure, biomarkers and behavioral outcomes were mixed. This is due largely to the variety of data collected and methods used across studies.
“We found consistent evidence that childhood violence exposure leads to reduced cortisol reactivity, which in turn increases the risk of aggression and delinquency later in life,” said Tracy. “While important, this is just one connection within a complicated web of different types of exposures, biomarkers and interactions between these factors — all of which require closer evaluation to eventually apply in a clinical setting.”
Studying Interconnected Systems
The study highlights key recommendations for future research. One observation is the need to diversify the kinds of biomarkers studied, and to assess multiple biomarkers, and their effects, in tandem.
“We found that many papers in our analysis looked at cortisol, which is widely studied and commonly known as the stress hormone”, explained lead author Jesslyn Chong, a clinical psychology doctoral candidate in the Department of Psychology. “But there are so many other biomarkers and systems that play an important role in stress response.”
The human body orchestrates an intricate repertoire of stress responses that play out in different systems and affect our most important functions — breathing, heart rate, cognition and digestion among them. When a stress triggers a change in any of these systems, this will cause other systems to respond. If something disturbs these chain reactions, there could be problems.
“Consider the autonomic nervous system — the two-armed regulator of the body’s involuntary processes, which includes the sympathetic and parasympathetic nervous systems,” said Chong. “These systems control stress responses like saliva stimulation/inhibition and pupil dilation/contraction. When working properly, these systems balance each other out. For example, when the sympathetic nervous system increases heart rate in response to stress, the parasympathetic nervous system helps reduce it when the stressor abates. If these two systems fall out of sync, that could increase the risk of adverse outcomes.
“If we only look at one aspect of this system, we’re only getting a fraction of the story — and this is just one of many interacting systems in the body. Our review highlights the need to undertake studies that look at multiple bodily systems, together with social and environmental factors, so as not to miss important interactive effects.”
Tracy emphasized that timing is another critical component in this work.
“We need to not only look at what factors interact and influence behavior, but when do those factors come into play? For example, during puberty, when the body is undergoing intense hormonal changes, the timing of these changes could play an important role in how other environmental factors are processed or received. Understanding when certain factors are having their peak influence can inform when clinical interventions might have the most impact.”
Clinical Implications
In a clinical setting, understanding biomarkers associated with negative behavioral outcomes could help screen for those at high risk who might benefit from various early interventions.
It is also important to consider how these biomarkers might influence response to different kinds of treatments.
“If you know that someone is at high risk because they have exposure to childhood violence, understanding their stress response system and the patterns that you see in the biomarkers might also influence how effective certain treatments might be. This could help practitioners identify treatments and interventions that are more closely tailored to the individual’s needs,” said Tracy.
Joining Forces to Dive Deeper
Tracy explained that bringing together collaborators from different fields allows for depth of study that would not be possible within a more isolated frame.
“In public health, we often focus on behavior as the main factor of interest,” Tracy said. “In criminology, they tend to focus on environmental and behavioral factors and how they influence risk of different kinds of crime. In psychology, biology is the typical focus — for example, how your stress response system might influence your response to different types of violence.
“A major aim of this project is trying to merge ideas from different disciplines together in a way that illuminates the bigger picture of the many different factors that influence violence, particularly after someone is exposed to violence in childhood and how that might shape their path moving forward.”
“It is widely recognized that childhood environment shapes later-life outcomes, but to understand how those links work, we must pay attention to social conditions, family environment, biology and psychology,” said coauthor Kate Strully, associate professor in the Department of Sociology. “Often, these different influences work together in complex ways and the effects of an environmental exposure depend on concurrent biological or psychological factors. I appreciate how this interdisciplinary work takes this complexity into account, drawing critical connections between the early life environment, physiology and later outcomes.”
The study was published this month in the journal Psychoneuroendocrinology.