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Why Do Events That Happened So Long Ago Still Harm Us?


Since 1998, research has consistently demonstrated that Adverse Childhood Experiences (ACEs) predict adult health problems ranging from headaches and obesity to depression, anxiety, autoimmune disorders, heart disease, cancer, and sleep disorders. But how do events that occurred way back in childhood continue to affect our health so many years later? Let’s see how this happens, for gaining an understanding of the mechanisms will later point us to ways to break the ACEs/adult health link.

ACEs ModelSource: Schiraldi, G. R. 2021. The Adverse Childhood Experiences Recovery Workbook. Oakland, CA: New Harbinger. ©2021 Glenn R. Schiraldi, Ph.D. Not to be copied.

As the diagram above shows, dysregulated stress is central to the ACEs/health outcomes relationship. Toxic stress in childhood can imprint and change the brain, biology, and sense of self in ways that affect adult well-being throughout life, if not addressed.  This is why the originator of ACEs research, Dr. Vincent Felitti, stated that we err to treat the smoke (stress-related conditions) without treating the flame (the underlying wounds from childhood that cause and maintain dysregulated stress). Dysregulated stress disrupts all systems of the body, including these.

Neurological Systems

Overwhelming stress in childhood, particularly during the brain’s tremendous growth spurt in the first three years of life, influences brain development in ways that keep the brain on high alert. During this growth spurt, traumatic experiences register not in the not-yet-developed (verbal/thinking) left brain, which will later be able to recall memories consciously with words and reason, but in the relatively well-developed right brain. The right brain, with its strong connections to the emotional, and survival regions of the brain, oversees non-verbal, non-conscious processing of memories. It imprints childhood memories, which are experienced as images, sensations, visceral states (e.g., sick to the stomach; constriction of the throat; survival tendencies, such as tensing muscles and preparing to run away) and a strong feeling tone (a felt sense of nameless dread; a sense of inadequacy, depression, shame, anxiety, and so forth). Even after the left brain more fully develops, the right brain will remain dominant for emotional processing of traumatic memories because the left brain goes off-line during overwhelming stress. It’s as though the brain says, “This is an emergency. There is no time to speak or reason with the threat. Right brain, take over.” If unaddressed, the patterns of danger and high alert that are imprinted in the right brain tend to persist, beneath the level of conscious awareness, over the lifetime.

Dysregulated Stress Hormones

Overwhelming stress can cause over- or under-secretion of stress hormones. (Under-secretion can result from chronic stress that exhausts the supply of stress hormones.) Cortisol is a major stress hormone that helps the body mobilize for fight or flight. It is usually helpful in the short term. For example, cortisol converts protein to sugar to provide fuel for the stress response. Dysregulated cortisol, however, is linked to:

  • Obesity
  • Elevated blood sugar and diabetes
  • Inflammation—a common culprit in a wide array of disorders
  • Immune dysfunction (Too much cortisol suppresses immunity, leaving us vulnerable to colds, flu, and other infections. Too little cortisol allows the immune system to become over-reactive, putting us at risk for autoimmune disorders. Toxic stress in the early years can impair the immune system’s ability to distinguish friend from foe.)
  • Impaired brain and lung development resulting from the conversion of protein to sugar
  • Disrupted sleep and mood
  • Harmful changes in epigenomes and telomeres. The epigenome sits alongside DNA strands and determines gene expression, and therefore how the brain develops. Cortisol also shortens telomeres, the protective “cap” of the chromosome, which also disrupts proper brain development.

What Have We Learned So Far?

Toxic childhood stress can profoundly and continuously affect the adult’s brain and biology. Dysregulated stress is central to the ACEs/health outcome relationship. Reducing the suffering of adults affected by the wounds from childhood adversity starts with regulating dysregulated stress—meaning we bring stress arousal levels within tolerable limits—neither too high nor too low. This allows the brain and body to restore physical health. Regulating stress also allows the brain regions that were pushed off-line by overwhelming stress come back on line— including the verbal, logical left brain and the regions that give us an integrated sense of self. This prepares the adult to process, settle, and rewire the inner wounds—the troubling memories that were imprinted in the first eighteen years of life.  

This blog has mainly addressed how dysregulated stress from ACEs changes our brain and biology. Our next blog will explore how ACEs change our psychology in ways that maintain dysregulated stress. Ultimately, this understanding will help us to apply the principles and skills that facilitate healing, well-being, and optimal functioning.


  • Reference. Schiraldi, G. R. (2021). The Adverse Childhood Experiences Recovery Workbook. Oakland, CA, New Harbinger.
  • This article first appeared in Psychology Today blog, October 5, 2021.
  • Title Photo: Andrea Piacquandio/Pexels

About the Author

Glenn R. Schiraldi, PhD, has served on the stress management faculties at The Pentagon, the International Critical Incident Stress Foundation, and the University of Maryland, where he received the Outstanding Teacher Award in addition to other teaching/service awards. His fourteen books on stress-related topics have been translated into seventeen languages, and include The Adverse Childhood Experiences Recovery Workbook, The Resilience Workbook, The Post-Traumatic Stress Disorder Sourcebook, and The Self-Esteem Workbook. The founder of Resilience Training International (, he has trained laypersons, emergency responders, and clinicians around the world on various aspects of stress, trauma, and resilience.

Dr. Glenn SchiraldiCover With Border copy


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  • Dr. Glenn Schiraldi
  • The Adverse Childhood Experiences Recovery Workbook
  • ACEs Model: Source: Schiraldi, G. R. 2021. The Adverse Childhood Experiences Recovery Workbook. Oakland, CA: New Harbinger. ©2021 Glenn R. Schiraldi, Ph.D. Not to be copied.

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Do you include adoptees as part of your ACEs research? If not, please consider adding adoptees. My suggestion is based on a book by Nancy Newton Verrier, titled “The Primal Wound.” The book focuses on pre-and perinatal psychology, attachment, bonding and loss. It clarifies the effects of separation from the Birthmother on adopted children.

Thank you, Tim

Spouse of a Birthmother (reunited after 45 years)

Hi Glen, would you like to have a page on my website to explain how a domestic homicide impacts on children in this way, I am sure there will be professionals and carers that will go to my website after a domestic homicide, we are just collecting content ready to upload at the moment.

Trauma from unchecked toxic abuse typically results in a helpless infant's/toddler’s brain improperly developing. I consider it to be a form of brain damage. If allowed to continue for a prolonged period, it can act as a starting point into a life in which the brain uncontrollably releases potentially damaging levels of inflammation-promoting stress hormones and chemicals, even in non-stressful daily routines.

The lasting emotional/psychological pain from such trauma is very formidable yet invisibly confined to inside one's head. It is solitarily suffered, unlike an openly visible physical disability or condition, which tends to elicit sympathy/empathy from others. It can make every day a mental ordeal, unless the turmoil is treated with some form of medicating, either prescribed or illicit.

I understand that my brain uncontrollably releases potentially damaging levels of inflammatory stress hormones and chemicals, even in non-stressful daily routines. It's like a discomforting anticipation of ‘the other shoe dropping’ and simultaneously being scared of how badly I will deal with the upsetting event, which usually never transpires. (Although I’ve not been personally affected by the addiction/overdose crisis, I have suffered enough unrelenting ACE-related hyper-anxiety to have known and enjoyed the euphoric release upon consuming alcohol and/or THC.)

Regarding early-life trauma, people tend to know (perhaps commonsensically) that they should not loudly quarrel when, for instance, a baby is in the next room; however, do they know about the intricacies of why not? Since it cannot fight or flight, a baby stuck in a crib on its back hearing parental discord in the next room can only “move into a third neurological state, known as a ‘freeze’ state … This freeze state is a trauma state” (Childhood Disrupted, pg.123). This causes its brain to improperly develop.

Also, how many non-academics are aware that it’s the unpredictability of a stressor, and not the intensity, that does the most harm? When the stressor “is completely predictable, even if it is more traumatic — such as giving a [laboratory] rat a regularly scheduled foot shock accompanied by a sharp, loud sound — the stress does not create these exact same [negative] brain changes” (pg.42). Furthermore, how many of us were aware that, since young children completely rely on their parents for protection and sustenance, they will understandably stress over having their parents angry at them for prolonged periods of time? I did not know any of the above until I heavily researched the topic for specifics.

Last edited by Frank Sterle Jr.
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