• By Laura Whybra
  • Posted on Friday 29th November, 2013

Stress hormone measurement – a new addition to the prevention science toolkit?

strong>Physical or emotional abuse and neglect at an early age can alter the development of children’s biological stress responses – but how might that knowledge be put to positive use by those who plan and evaluate prevention services?Evidence has been accumulating in recent years about the links between compromised physical, psychological and social development among maltreated children and impairments to their neurobiological responses to stress. The hypothalamic-pituitary-adrenocortical (HPA) system –responsible for regulating bodily processes such as mood, emotion, and digestion – has become a particular focus for research, yielding evidence of ways that early ill-treatment can lead to changes in levels of the stress hormone cortisol.However, as a review by Jacqueline Bruce of the Oregon Social Learning Center, Megan Gunnar of the University of Minnesota and colleagues makes clear, there are still major challenges to be overcome before prevention science can make much practical use of stress neurobiology in the design and evaluation of interventions.For example, while abnormal regulation of a child’s HPA system has been implicated in the onset of depression, post-traumatic stress disorder and behavioral disorders, it can impact on healthy development in differing ways. Both elevated and lowered cortisol can be dysfunctional in different circumstances. And whether an individual’s levels are high or low can vary according to gender, age, current exposure to stress and the types of abuse or neglect they have experienced (physical or emotional, for example).Potential for progressThe authors, nevertheless, suggest three ways that evidence of neurobiological stress, obtained by measuring cortisol levels, could eventually serve to improve prevention strategies and interventions:Firstly, it could make it easier to identify children who are most in need of services to prevent long-term harm to their mental or physical health. For example, research has shown that children exposed to multiple caregiver transitions tend to exhibit elevated cortisol levels, as do those that have experienced several different types of maltreatment. However, the use neurobiological stress measures as a screening tool would require better understanding of the circumstances and levels of cortisol where children should be considered “at-risk”. Secondly, the authors point to ways that measuring cortisol patterns can help identify the pathways that enable effective interventions to “work”. For example, a study of Multidimensional Treatment Foster Care for Preschoolers (MTFC-P) – a preventive intervention emphasizing the use of consistent parenting strategies – researchers found that children receiving the service had typical cortisol levels, whereas levels among a control group who did not were reduced. Even more interestingly, the MTFC-P trial provided evidence that the intervention reduced levels of caregiver stress – a factor known to be associated with disrupted cortisol levels in children. So in addition to providing an indication of the program’s effectiveness, cortisol measurements provided insight into a mechanism through which positive change was being achieved.Thirdly, cortisol measurements can provide insight into how and why children respond differently to interventions. Evaluation studies frequently find interventions have had a stronger impact on some children or families than on others. Children’s biological stress responses appear to be one of the factors that can make a difference. For example, one study found that children with blunted cortisol response when exposed to psychological stress also responded poorly to a group-based intervention for preventing behavioral disorders. Potential for delayGreater understanding of changes in the biological stress responses of children who have been exposed to early adversity brings an increasing likelihood that prevention and early intervention work will benefit. But the complex nature of the human body’s biological stress systems (of which the HPA system is just one) mean their practical use in early intervention is unlikely to be imminent. There needs to be more research into the impact of cortisol on child development and its possible impact on the effectiveness of interventions. But more attention also needs to be paid to fundamentals, such as greater consistency in the way that stress processes are defined and measured.***************Reference:Bruce, J., Gunnar, M. R., Pears, K. C., & Fisher, P. A. (2013). Early Adverse Care, Stress Neurobiology, and Prevention Science: Lessons Learned. Prevention Science, 14, pp. 247-256.

Back to Archives