How Does Stress Affect the Brain?
By: Sam Ernst
Let’s talk about stress.
We all experience stress, and there are many of us who experience high levels of stress every day, whether that’s due to work pressures, financial strains, or relationship difficulties. In fact, a 2017 survey conducted by the American Psychological Association (APA) found that 43% of Americans cited health care as a major stressor, followed by: the economy (35%), trust in the government (32%), crime and hate crimes (31%), and terrorist attacks in the US (30%).
Not only are adults stressed, but teens and children in the US are reporting high stress. Results from the most recent Youth Risk Behavior Surveillance System show that 70% of high schoolers “often or very often felt stressed by school” (read more here: https://apcyf.arlingtonva.us/wp-content/uploads/sites/41/2017/10/2017-SUMMARY-OF-RESULTS.pdf).
As their brains and bodies are still developing, youth are particularly vulnerable to the effects of stress. Childhood stress, and particularly exposure to its most severe and chronic forms, including things like abuse, or poverty, is known to associate with poor physical and mental health, not only during childhood and adolescence but also even into adulthood. However, the biological mechanisms explaining how stress and adversity creates vulnerability to disease and psychopathology are not well understood.
Researchers are beginning to make headway in understanding how stress gets “under the skin”. For instance, one neurophysiological system – the hypothalamic-pituitary-adrenocortical (HPA) axis – has been studied quite intensively with regards to its role in the body’s stress response. The HPA axis is a negative-feedback loop that controls the steroid hormone cortisol in reaction to stressful situations. Although some stress is actually beneficial to our everyday functioning – just think about the motivation you get due to the stress of a deadline at work! – the HPA axis is often dysregulated among people who experience chronic stress, including children who are maltreated.
A recently published review by Koss and Gunnar (2018) in the Journal of Child Psychology and Psychiatry summarizes current evidence on role of the HPA axis in explaining the link between childhood adversity and psychopathology. They note increasing support for the link between childhood adversity and altered HPA axis activity. They also note that the relationship between adversity, HPA axis function, and psychopathology varies based on: the age of the child, degree of prior or current adversity, and the type of psychopathology examined.
They also emphasize that many questions remain unanswered. For example: How does understanding biological change following exposure to childhood adversity help to increase understanding of future psychopathology risk? Can interventions decrease vulnerability to such biological changes? When during the course of development are children most vulnerable? These questions are complex and will require more ongoing research, but I am hopeful that discoveries in the next decade will help to address these issues.