How Do Various Cortisol Levels Impact Cognitive Functioning?

Various levels of “the stress hormone” cortisol affect cognitive development.

Posted Jun 17, 2015

Children who grow up in stressful environments often have elevated levels of "the stress hormone” cortisol, which can impair cognitive development. New research shows that some children growing up with adversity actually have low levels of cortisol, which is also linked to compromised cognitive functioning.

A new study has identified how specific levels of cortisol affect the cognitive development of children who are growing up with the stress associated with family adversity, living in poverty, and/or homelessness.

The June 2015 study, “Tracing Differential Pathways of Risk: Associations Among Family Adversity, Cortisol, and Cognitive Functioning in Childhood,” was conducted at the University of Rochester, the University of Minnesota, and Mt. Hope Family Center, and published in the journal Child Development

The statistics of childhood poverty are alarming. It’s estimated that four out of every ten American children currently live in low-income households, according to research from the National Center for Children in Poverty at Columbia University's Mailman School of Public Health.

Pixabay/Public Domain
Source: Pixabay/Public Domain

The primary aim of the recent study was to gain a better understanding of how various cortisol levels impact a child’s social–emotional adjustment, as well as, his or her language, motor, and cognitive functions.

The researchers found that children with relatively high or relatively low levels of cortisol are more likely to experience learning deficits and cognitive delays.

Cortisol is generally referred to as “the stress hormone” because it’s secreted into the bloodstream in larger quantities during stressful situations or any environment that triggers the flight-or-fight response.

There are two kinds of stress: good stress (eustress) and bad stress (distress). Optimal levels of cortisol may be linked to eustress. In certain circumstances, the right amount of cortisol fuels your passion and gives you the oomph needed to seize the day.

It appears that low levels of cortisol could be a biomarker for depression, apathy, or hopelessness about someone's possible futures. Elevated levels of cortisol could be directly linked to the distress caused by environmental stressors.  

Three Different Cortisol Profiles Impact Cognitive Functioning

University of Rochester
Source: University of Rochester

For the new study, researchers measured children's cortisol levels when they were two, three, and four years old. When each child was two years old, the researchers observed them playing with their mothers and collected extensive information about family dynamics, such as how stable the family home appeared to be and whether children had been exposed to domestic violence.  

When the children were four years old, researchers measured their cognitive abilities. The study found that children with relatively higher and lower cortisol profiles had reduced levels of cognitive functioning at age four.

In a press release, Jennifer H. Suor, doctoral student in clinical psychology at the University of Rochester and the study's first author explained the findings saying,

Overall, we found three cortisol profiles among the children, which were categorized as elevated, moderate, and low. We found that children's cortisol levels remained relatively stable across the three years. And we discovered that exposure to specific forms of family adversity when children were two years old predicted their cortisol profile, which in turn was linked with notable differences in children's cognitive functioning at age four.

The study reported that about 30 percent of the children in the study maintained relatively higher cortisol levels; 40 percent of the children maintained lower cortisol levels; and the remaining 30 percent maintained moderate cortisol levels. Interestingly, children on either end of the spectrum of cortisol levels had experienced some type of family instability.

Children with the highest cortisol levels had experienced harsher and more traumatic interactions with a caregiver or parent. On the flip side, children with moderate cortisol levels were exposed to relatively less family adversity at age two and also had the highest cognitive abilities at age four.

The researchers are unsure of the exact mechansims that link cortisol levels and cognitive functioning. They hypothesize that too much cortisol may have toxic effects on parts of the brain that are important for cognitive functioning. Too little cortisol might impede the body's ability to recruit the biological resources necessary for optimal cognitive development.

Conclusion: Safe and Stable Home Environments May Optimize Cortisol Levels

There appears to be a range of cortisol levels in response to childhood stress for any child who's experiencing poverty, an unstable home environment, or homelessness. The results of this new study indicate the importance of cortisol screening and access to early interventions for vulnerable children.

The study also illuminates the importance of working closely with a caregiver or parent who might have difficulty tuning-in to a child's needs. In a press release, Melissa L. Sturge-Apple, assistant professor of psychology at the University of Rochester, who was part of the research team summed up the findings,

Low-income children are at increased risk for developing cognitive delays, but the specific environmental and biological factors that influence these outcomes are less understood.

Our study shows that children's cortisol activity and the experience of specific family adversities may be key processes that predict cognitive development for children from low-income backgrounds. The findings can inform preventive interventions, especially those that can reduce family stress and strengthen parent-child relationships, because these may promote healthy cortisol levels in children and, in turn, may result in positive cognitive outcomes. 

The researchers hope that future studies will investigate specific factors associated with resilience among children and ways to optimize levels of cortisol and cognitive functioning.

If you'd like to read more on this topic, check out my Psychology Today blog posts:

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