I'll open by saying, we don't fully know... yet. (I certainly don't anyway) but developments over the last five years have put a way bigger light on how childhood trauma effects the brain, what the adult version of childhood trauma looks like, and I'm specifically investigating how that expresses in business.
PSA: This blog post is for educational purposes only. It is not meant to diagnose, treat or in any way act as advice. Engaging a qualified trauma-informed medical practitioner is strongly advised. This content is being shared as I document what I am learning in this field of study and how it has made my own struggle with mental health, better. If you're in Ireland, I am a big fan of Pieta House. I raise money for them, and would happily put them forward as one (of many) resources that may be of support for you, should you want it.
Side Bar: I have recently (2023) shifted my business focus into academia as I pursue my PhD in the area of childhood trauma in business. It is my intention to use Moody Cow as a personal platform to document my learning, share insights and provide a look behind the curtains as to what this academic journey is like. I will remain at NB3, as an advisor, delivering programs, training and workshops for business seeking ways to perform better in the area of business, culture and people.
As part of the foundational look at childhood trauma in business, I want to introduce an insight that I stumbled across a few years ago that moved me so deeply, it would be about 6-weeks later before the impact of its discovery faded.
Here is that insight:

Childhood Trauma in Business starts here:
This brain scan image matters a lot for a very simple reason.
Your brain came 'online' at the start of the third trimester in-utero. Your brain continued to develop until it was fully formed through to age 5. Between the third trimester in-utero and age 5, your primary caregiver(s)' stress levels, ability to face and recover from hardship, was handed down to you as the imprint for your brain's formation to follow, while at the same time, the experiences of your early years were directly involved in shaping the formation of your brain, its wiring, its connections, or the absence thereof.
Fast Forward 15 years, and that brain (on the right- above), continues to look and operate very differently from that brain on the left. The experiences the 15 year old is having are reinforcing the wiring, programs and connections into adult hood.
That 15 year old, now a 40 year old manager in let's say, a Financial Services Tech Start Up, has a very different experience of the world, than his or her colleagues who came from a loving childhood with caregivers who installed healthy programming.
About 20% of individuals with childhood trauma in their background, develop CPTSD as adults. Let's call that one end of the mental health spectrum.
On the other end, is varying levels of anxiety, depression, inability to focus, can't prioritise, easily triggered, has higher levels of absenteeism, develops autoimmune disease, and will struggle enormously in social environments where making meaningful connections with others feels threatening, never mind a little challenging.
Overwhelm will play a bigger part in their life compared to those that come from loving, healthy homes. The ability to self-regulate that overwhelm will be fractured - as childhood trauma impacts the brain-stem, responsible for self-regulating.

How childhood trauma effects the brain:
The front of the brain is less active - so logic, reason, behaviour, decision making is effected.
Your pre-frontal cortex is up to 30% smaller in adults with childhood trauma in their history.
The back of the brain is more active - an area largely about perceived threat that controls the stress hormones and automatic function of us humans.
Your amygdala is hyper active, to levels of extreme alert, and 'always-on' - a hallmark trait of people with childhood trauma in their past.
The right side of the brain where emotions and being-social lights up more than it should. Let me put a wee proverbial stick it note here against this one. We talk about passing a baton to the body shortly... this point has a lot to do with that upcoming comment.
The left brain less active. Logic, reasons and the ability to solve complex puzzles.
The communication between areas of the brain can also be impaired and/or severed. Parts of the brain move into forms of paralysis - or - overdrive. Consider, that any of these imbalanced states cause the body to respond with 'extra stuff'. That extra stuff, over time becomes toxic in the body.
'I know what I am supposed to do, but I just can't do it!'
That used to be one of my most popular go to "mantras" that I would speak out loud, with gobs of frustration to go with it, or think silently to myself as I yet-again, punish myself for not being able to just 'shake it off' or 'just do it' or any version thereof.
The cognitive self is helpful in reprogramming the legacy models from our childhood, but it must hand the baton to the Body in order to complete the processes needed to effect long term reprogramming.
Cognition allows us to 'bring into our awareness' crucial information, that will metabolise in our self, days after it's been introduced. Cognition also allows us to do the research, learning, reading required to ensure Awareness is accompanied with ever increasing levels of understanding.
However, it's about then, (deeper level of understanding) that the mind needs to pass the proverbial baton to the Body to complete the reprogramming requirements that are still outstanding that cognition cannot effect.
And therein lies years of my own personal struggle.
I read, studied, attended workshops, invested in programs years long, and did all the cognitive stuff required, and a whole bunch of extra to boot.
I was dog-with-a-bone determined to change myself. Thus the mantra - I know what I am supposed to do, but I just can't do it - took center stage when my life had already spent thousands of hours invested in personal study, and yet, continued to demonstrate minimal to no change.
Ohhh the anguish, the shame, the blame, the helplessness that often felt hopeless, and all the questions: 'what is wrong with me?', 'why can't I, when they can?' rolled out and took up residence in my space until enough time had passed where I could forget the past experience of 'failed attempt' enough, to let myself think, this next book, this next course - it looks like it could be it. HAH!

I'm guessing you already know the answer to what happened with said, next book?
I had no idea there was a baton to pass.
I didn't understand the role of the body enough in my desired reprogramming, and I definitely didn't appreciate, respect or fully get how to pass metaphorical baton to my body. Even now, I wonder if I had seen or heard this explanation 10 years ago, would I have even understood it then? I doubt it.
Over the coming year, I will be talking about the Mind/Body communication for changing the legacy programs that we picked up as kids.
You are welcome to hit subscribe below to get updates, or just follow me on FB, Insta or LinkedIn to see things pop up as and when.
If you have specific questions you'd like answered anonymously in the blog or podcast, please email me shannon at nb3 dot io - of if you'd like to discuss, debate and share your own observations with me 1-to-1 or on a podcast, get in touch using the same email.

About that proverbial wee stick-it note.
I put a wee stick0it note half way up this post - next to the right brain bullet above - the area of the brain overseeing emotion, social connection. That part of the brain is stuck in legacy programming and instrumental in the reprogramming we want. And often, we tend to try and 'Cognition' our way through it - pushing everything through the left side of the brain - logic, reason, fact.
Well - we need both to effect long lasting change.
The baton is passed to the body when we deliberately enter a state of being present, supported by breath work, while we engage the communication held in the body (yes - you read that right - think of this as your unconscious self) that gets processed and made complete, all while we are being present, actively inside breath work, and ideally, being facilitated by a trauma-informed practitioner.

I appreciate that this isn't something you can now take and do tomorrow to create the long lasting change, but it is foundational and something that is to be brought into our awareness, which will metabolise over the coming days - and if you're anything like me, will shift a lot just by bringing it into your own awareness. I will be building on these ideas here on this blog, and over at the Moody Cow podcast.
References:
Standing on the Shoulders of Giants - a term credited to Sir. Isaac Newton when asked about his own work. Now a term I have a deeper appreciation of, for myself. There have been hundreds of proverbial giants who have inspired, supported and guided me along the way. In this are of childhood trauma specifically, some of those individuals include:

Ralph Waldo Emerson - and his essay on Circles was instrumental in my life, giving me a greater look at my ego, my rigidity, and my obsession with facts. The beginning of my exploration into my own trauma, circa 2014.
Confucius - his life story is an exemplary example of how to greet set backs, stay centered in the face of challenge, and show kindness while caring for your own person simultaneously. His piece on grief has been something I've referred to quite a bit over the years.

Einstein - so much of him, the man, and his work have been a source of enormous inspiration; being misunderstood, flawed, and irritating to those who loved him, while recognising from childhood his heart's calling was to be pursued, come what may.
Some of his life choices create a clear example of everything having drawbacks and benefits in equal. And what we may perceive as being better, than an alternative option, simply proves to be a 'different' option bringing with it as much drawbacks as benefits, in equal. We simply get to choose which set of drawbacks and benefits we are prepared to live with.

Dr. Gabor Maté - the Jewish, Canadian doctor who first introduced me to the brain scans of the two children through his own life's work of treating addiction. His video content is excellent. His book - when the body says "No", is worth checking out too.
Dr. Bessel van der Kolk - one of the world's leading researchers and practitioners of how childhood trauma effects the brain. His book - The body keeps the score is a big read, and one worth taking if it resonates.
Dr. Steven Porges - and his work in Polyvagal theory may be a timely read for you, if this topic is of interest. I was introduced to this work in 2015, but didn't get involved in it in any meaningful way until 2017.
Dr. Bruce Lipton - The Biology of Belief is a book I've consumed 100s of times over. He also has a youtube video where he delivers the contents of his book to a class at uni. Approx. 2.5hours in length and dropped in here for easy viewing.