Is Adolescence a Chance to Reset Development?

In 2005, the Harvard Center on the Developing Child began its landmark paper on the impact of excessive stress early in life with these words:

Extensive research on the biology of stress now shows that healthy develop­ment can be derailed by excessive or prolonged activation of stress response systems in the body and the brain, with damaging effects on learning, behavior, and health across the lifespan.¹

In the paper, they introduced the concept of “toxic stress,” which they differentiate from positive and tolerable stress, defining it as a strong stress reaction that takes place over time and is experienced by children who don’t have access to the support of caring adults.

The language the Center chose to use was intentionally designed to be disturbing because the findings were disturbing:

The regions of the brain involved in fear, anxiety, and impulsive responses may overproduce neural connections while those regions dedicated to reasoning, plan­ning, and behavioral control may produce fewer neural connections.²

For the last 20 years, I’ve heard early childhood advocates take up this mantel arguing that early stress like abuse and neglect is lethal because it derails human development and is toxic to brain development.

Lethal implies forever. Is this true?

Not so, says more recent research. Early adversity is not destiny.

In their consensus report on adolescence, the National Academies of Sciences, Engineering, and Medicine evaluated programs and interventions that build on the plasticity of the adolescent years, revealing that it is possible to positively affect young people’s psychology and physiology to help them thrive.³ They conclude:

While preventing early-life adversities is ideal, research shows that ameliorating and redirecting an unhealthy developmental trajectory remains possible during adolescence and later developmental periods.⁴

Megan Gunnar of the University of Minnesota was one of the scientists on the National Scientific Panel at the Harvard Center that produced this landmark paper in 2005 and questions of whether subsequent experiences can reset development have concerned her ever since.  She has a unique background in psychology and in the relationships among the endocrine or hormonal system, the nervous system, and psychology that make her an ideal scientist to study these complex developmental issues.

Gunnar defines stress as a time when the “demands on your body—or your expectations of those demands—exceed your ability to handle them.”⁵ The stress system is what she calls a “fast on–fast off system.”⁶ It revs up quickly, then tamps down the reaction once the perceived danger is over. But if stress is prolonged and this system is turned on frequently, it can change how the body and the brain function.

Her driving question became: What if stress is severe and frequent in the earliest years but then subsides?

A trip with a research team to an orphanage in Romania in the mid-1990s set Gunnar on a path to answer that question. She saw children in overcrowded and inhumane conditions. Even when their physical needs were met, they weren’t able to form relationships to meet their psychological needs.⁷ Post-adoption, the adversity subsided—these children tended to be adopted into loving and caring homes. Gunnar and her colleagues created a registry of six thousand children adopted from international orphanages worldwide and conducted numerous studies over time.⁸

They did find that children who experienced deprivation and neglect for two or more years in orphanages with the poorest quality of social care were likely to have a blunted or reduced (hypoactive) stress reaction. Since stress was omnipresent in the harsh orphanages, Gunnar says that the children’s bodies eventually had to dial down their reactions—perhaps as nature’s way of preserving their brains and bodies.⁹ This blunting effect, they found, lasted long after the children left the orphanages—well into the elementary school years, suggesting there is a sensitive period during the early years where a blunted stress response appears to become established.¹⁰

The name—a hypoactive stress system—can make it seem as if children are passive in the face of challenges, but it’s more than that. Gunnar and other researchers have found that children with a blunted cortisol reaction are at risk for a number of other problems compared with children in similar socioeconomic situations but raised by their biological parents:

[They] have been found to experience more social and emotional problem behaviors, have greater difficulty understanding social cues, are more likely to experience difficulties in social situations with peers, and have trouble establishing and forming healthy social relationships.¹¹

Led by then–graduate student Carrie DePasquale, Gunnar and their team then found cascading effects: the young children with a blunted cortisol reaction are less likely to be socially competent,¹² have more problems in regulating their emotions and behavior as kindergartners,¹³ and are more likely to be socially anxious as youth.¹⁴

Importantly, their lab studies have found that the quality of parenting provided to these young children post-adoption in their new homes did make a big difference. For example:

• Parents who are sensitive and who provide more structure are likely to have children with better emotional regulation skills.¹⁵

• Parents who are consistent in providing routines have children who are likely to have better inhibitory control and fewer attention problems.¹⁶

• Parents who are supportive and (the “and” here is necessary) who provide structure and set appropriate limits are less likely to have children who are socially inappropriate.¹⁷

Still, the blunted cortisol reaction remained in place, leading Gunnar to ask, “If moving the child from an institution into a well-resourced family with parents who score (generally) high in parenting quality doesn’t ‘fix’ the axis, will anything?”¹⁸

The “anything” she and her colleagues suspected was puberty. They hypothesized that “puberty would open a window when the stress system could be recalibrated.”

To find out, they conducted a study with 299 seven-to-fifteen-year-olds, 129 of whom were adopted after being in orphanages as infants and toddlers, and 170 of whom were born and raised by their biological families. Three times over the next two years, beginning when the children were ages seven through fifteen, they were given the Trier Social Stress Test—“one of the most reliable stressor-tests in the literature.”¹⁹

Reading about the Trier may bring back school memories (or nightmares). Participants are asked to give a five-minute videotaped speech introducing themselves to imaginary classmates, stating a few things that would make other kids want to be their friend and a few things about themselves that are not so great.

They have five minutes to prepare and write notes but can’t use notes during their speech. If they pause while they are speaking, they are told to “say more about that” or “keep going.”

After the speech, participants are asked to do difficult mental arithmetic problems aloud. When they make a mistake, the experimenter says, “Wrong. Start over.” 

It is stressful. I’ve watched young people rub their hands and squirm during this test. The young people are asked to spit into a straw five times during their lab visit so the researchers can measure the rise and fall of their cortisol, which takes about twenty-five minutes to peak in stressful situations. 

The results? The researchers’ hypothesis was correct: “We found beautiful evidence of recalibration!”²⁰ Gunnar exclaims. Puberty offers a window for the young people to develop new stress responses.

While these data are very hopeful,²¹ it’s not a completely “happy-ever-after story,” Gunnar says.²²

Their team conducted a subsequent study to find out if the increased (i.e., now normal) cortisol reactivity among these adolescents would mean reduced behavior problems. They looked at externalizing problems, like being oppositional, defiant, and aggressive, and found that increases in stress reactivity were not linked to more oppositional problems or vice versa.

However, there was an association with internalizing problems—depression and anxiety. Increases in reactivity were linked to increases in these problems, and the reverse was also true: internalizing problems were linked with increased cortisol reactivity.²³ But they state that only 3 to 4 percent of these adolescents would be classified as depressed or anxious at a clinical level, where professional treatment would be recommended.

Clearly, these adolescents NOW have to learn to manage their less blunted reaction to stress.

Gunnar’s team studied the quality of parenting that was naturally occurring and found that it made a difference for children who’d been adopted from orphanages. But what if there were efforts to identify the most important aspects of early parenting and increase them at that time? That’s been a goal of Philip Fisher of Stanford University.

Fisher recognized that parenting children with blunted stress reactions can be challenging because, as he puts it, children remain “closed in”—they are less likely to notice or respond to being nurtured, which in turn makes it harder for parents to notice these “weak signals” from children or to stay positive.²⁴

The parenting ingredient Fisher’s team selected is “serves and returns”—when children initiate an interaction with parents (serves), and parents respond in caring and supportive ways (returns), leading to more positive back-and-forth interactions.²⁵

They called their intervention FIND (Filming Interactions to Nurture Development). It was designed to make parents of young children aware of the importance of serves and returns and to increase them. Parents videotape themselves with their child; the researchers watch the videos, pinpoint moments where there are serves and returns, and show them to parents via video coaching.²⁶

Fisher says that the results are “magical”: a preliminary evaluation of FIND concluded that increasing awareness and changing behavior are possible and that they’re linked to positive changes in parents’ own brains.²⁷ Fisher says:

We saw changes at the level of brain activation in those areas of the brain around self-control and we know that self-control is one really important part of executive functioning, so it was a very exciting finding.²⁸

While interventions like FIND haven’t been tested over time, another intervention for children younger than two-years-old with reported abuse has and it offers the promise of an even happier-ever-after story.

This 10-session intervention led by Mary Dozier of the University of Delaware²⁹ is called ABC and it has three aims: 1) to increase parental nurturing when the child is in distress, 2) to improve back and forth interactions between the parent and child, and 3) to decreased frightening parental behavior. Parent coaches also provided feedback to parents live and via videos. An evaluation at the time of the intervention found that the program normalized children’s daytime cortisol levels in comparison with the control group who still showed a blunted response. Importantly, the effect of this intervention lasted three years later when the participating children were preschoolers!

As the research in this field continues, one thing is clear for children whose families who didn’t have the opportunity to participate in programs like FIND or ABC when their children were young. The plasticity of the brain during adolescents provides many new opportunities to help children thrive, even children who had very, very difficult beginnings.

1. National Scientific Council on the Developing Child. (2005/2014). Excessive Stress Disrupts the Architecture of the Developing Brain: Working Paper 3. Updated Edition. 1, http://www.developingchild.harvard.edu.

2. Ibid., 2.

3. National Academies of Sciences, Engineering, and Medicine, The Promise of Adolescence: Realizing Opportunity for All Youth (Washington, DC: National Academies Press, 2019), 11, https://doi.org/10.17226/25388; Gene H. Brody et al., “Protective Prevention Effects on the Association of Poverty with Brain Development,” JAMA Pediatrics 171, no. 1 (January 2017): 46–52, https://doi.org/10.1001/jamapediatrics.2016.2988.

4. National Academies of Sciences, Engineering, and Medicine, The Promise of Adolescence, 70

5. Megan R. Gunnar, interview by Ellen Galinsky, September 26, 2001.

6. Megan R. Gunnar, interview by Ellen Galinsky, July 27, 2017.

7. Nicole B. Perry et al., “Associations Between Stress Reactivity and Behavior Problems for Previously Institutionalized Youth Across Puberty,” Development and Psychopathology 32, no. 5 (December 2020): 1854, https://doi.org/10.1017/S0954579420001297.

8. Megan R. Gunnar, email message to Ellen Galinsky, May 10, 2019.

9. Esther Landhuis, “Puberty Can Repair the Brain’s Stress Responses After Hardship Early in Life: Adolescence Could Be a Time to Reset the System That Helps People Cope with Stress,” Science News, August 28, 2020, https://www.sciencenews.org/article/puberty-teens-brain-stress-responses-early-trauma.

10. Megan R. Gunnar, email message to Ellen Galinsky, May 10, 2019.

11. Nicole B. Perry et al., “Cortisol Reactivity and Socially Anxious Behavior in Previously Institutionalized Youth,” Research on Child and Adolescent Psychopathology 50, no. 3 (March 2022): 375–385, https://doi.org/10.1007/s10802-021-00862-5.

12. Carrie E. DePasquale et al., “Cortisol and Parenting Predict Pathways to Disinhibited Social Engagement and Social Functioning in Previously Institutionalized Children,” Journal of Abnormal Child Psychology 48 (March 2020): 797–808, https://doi.org/10.1007/s10802-020-00633-8.

13. Kalsea J. Koss, Jamie M. Lawler, and Megan R. Gunnar, “Early Adversity and Children’s Regulatory Deficits: Does Postadoption Parenting Facilitate Recovery in Postinstitutionalized Children?,” Development and Psychopathology 32, no. 3 (August 2020): 879–896, https://doi.org/10.1017/S0954579419001226.

14. Perry et al., “Cortisol Reactivity and Socially Anxious Behavior in Previously Institutionalized Youth.”

15. Ibid.

16. Ibid.

17. Koss, Lawler, and Gunnar, “Early Adversity and Children’s Regulatory Deficits.”

18. Megan R. Gunnar, email message to Ellen Galinsky, May 10, 2019.

19. Megan R. Gunnar et al., “Pubertal Stress Recalibration Reverses the Effects of Early Life Stress in Postinstitutionalized Children,” Proceedings of theNational Academy of Sciences 116, no. 48 (November 2019): 23985, https://doi.org/10.1073/pnas.1909699116; Andrew P. Allen et al., “The Trier SocialStress Test: Principles and Practice,” Neurobiology of Stress 6 (2016): 113–126, https://doi.org/10.1016/j.ynstr.2016.11.001.

20. Megan R. Gunnar, email message to Ellen Galinsky, May 10, 2019.

21. Ibid.

22. Megan R. Gunnar, email message to Ellen Galinsky, May 10, 2019.

23. Perry et al., “Associations Between Stress Reactivity and Behavior Problems,” 1854–1863.

24. Philip Fisher, interview by Ellen Galinsky, July 10, 2017.

25. National Scientific Council on the Developing Child, “Young Children Develop in an Environment of Relationships,” Working Paper No. 1, Center on the Developing Child at Harvard University, 2004, https://developingchild.harvard.edu/resources/WP1/.

26. Nicole R. Giuliani et al., “A Preliminary Study Investigating Maternal Neurocognitive Mechanisms Underlying a Child-Supportive Parenting Intervention,” Frontiers in Behavioral Neuroscience 13, no. 16 (2019): https://doi.org/10.3389/fnbeh.2019.00016.

27. Ibid.

28. Philip Fisher, interview by Ellen Galinsky, July 10, 2017.

29. Kristin Bernard et al. “Intervention effects on diurnal cortisol rhythms of Child Protective Services-referred infants in early childhood: preschool follow-up results of a randomized clinical trial.” JAMA pediatrics vol. 169,2 (2015): 112-9. doi:10.1001/jamapediatrics.2014.2369