How Childhood Trauma Affects the Nervous System in Adulthood

How Childhood Trauma Affects the Nervous System in AdulthoodI was sitting on the club floor, crying to the beats of Silke Bischoff’s “On the other side, I’ll see you again.” I saw people dancing. I saw them laughing. I couldn’t move. I wanted to be one of them. My then boyfriend did not care. He was dancing with others, having fun. Back then, it felt normal, just who I was. That was a regular Friday evening in my early 20s.

I left home when I was 19, leaving behind darkness and violence. What I did not know was that I had taken my childhood with me. Back then, it felt normal, just who I was. Today I know what was happening on that floor. My nervous system was doing what had kept me alive at home. It just hadn’t learned yet that I had left.

I work with people who grew up with abuse and trauma. I tell them what I needed to hear back then: There is nothing wrong with you. Your nervous system is doing what it needed to do to help you survive at home.

How childhood experiences shape emotional regulation

Imagine a three-year-old crying. A parent comes close, holds her, and stays calm. The parent’s nervous system tells the child’s: it’s a storm, and it’s okay. No single moment teaches that. Repetition does.

For me, it was different. When my grandmother died, I cried. I was scared of death. My mother asked me what was going on. I told her in tears. She looked at me, said, “Don’t be stupid,” and walked away.

Many of my clients know this too. A parent looked at them with disdain. Some five-year-olds were locked in a room for hours when they felt angry, and nobody asked what they were angry about. Often it’s passed down by parents.

In sessions, I ask: What would the child have needed in that moment? Someone who could stay with them through the storm. Someone who could show them that their emotions were not a threat to the relationship.

When the window of tolerance is narrow as an adult

The window of tolerance is the zone where you can still think and feel at the same time. Go above it, and you’re flooded: panic, rage, a body that won’t slow down. Go below it and you shut down: numb, flat, far away. On the club floor, I was below it. Read more: Window of tolerance for trauma.

A baby’s window of tolerance is tiny. It gets wider if an adult calms them, again and again. Just many parents don’t have the capacity.

Many of my clients swing. Anger or grief floods them, and then they go numb and flat. Some can handle irritation or disappointment, but not the big ones. Others shut down the moment shame shows up. Many are confused about what is happening inside. Some use alcohol or drugs to stop the swing. And when things finally calm down, the fear of the next shutdown gets bigger. Most don’t connect it with their childhood.

With my clients, we start with the body. I ask them to recall a memory when they were shut down, flooded or safe. Not all of it, just 10%. I ask what they notice inside. If the state had a colour, what would it be? The immobilized state is usually dark. Mobilized is often red. Once they can tell the states apart in their body, they start recognizing them in the present. Not after. In the moment.

In later sessions, if a client feels flooded, I offer grounding. Their breathing gets easier, the heart beats slower, the tension eases. If they shut down, we gently stimulate their nervous system, like wiggling the toes or connecting with the spine. A tingle. A yawn. The body comes back a little. We usually look for 5% improvement. That’s enough.

How childhood trauma shapes our responses to safety and danger

I sat in a car with a friend. She raised her voice. I felt her anger. I thought: how do I get out of the car? We were on a highway. I knew I couldn’t. I froze. I couldn’t speak. Looking back, I wish I had been able to say “stop yelling.”  

The window of tolerance is about what happens with emotions. Polyvagal theory, in simple terms, is about what happens in relationships. Here’s how it helped me make sense of the car: The nervous system reads danger and responds quicker than the mind. Her raised voice meant danger to mine. Something I had learned in my childhood. Danger isn’t always about the present. Listen to: Polyvagal theory and trauma.

The nervous system reads safety, too. Many of us could never fully learn as children what safety feels like. Some of my clients had one or two safe connections. Some had none. My grandmother was one for me. When I was sick, she cared for me. She read books until her voice was hoarse. Our cat was my secret companion when the tension at home was too much. I did not build safety from zero, though I had little to build on.

We built safety step-by-step, internally and with safer people. When a client who learned that setting boundaries is dangerous meets someone who respects theirs, their nervous system learns something different. My clients learn to listen to the warnings their nervous system gives them, to find their way back to calm, and to ask whether the warning comes from the past or the present. At times, they are both.

Here is my dilemma with “just do somatic practices and feel safe again.” Sometimes my body is reacting to a threat that’s from the past, and getting back to calm helps. Sometimes the relationship in front of me is the threat. I see this in clients whose partners have toxic behaviours. Their nervous system is responding to a behaviour that is actually happening and often repeated without accountability for change. Healing childhood trauma doesn’t mean you’ll always be safe. It means your nervous system becomes more fluent at getting back to safety and connection after a current or past threat. The work is telling which is which. Healing means having more choice.

If you’re BIPOC or queer, your nervous system also rightfully detects discrimination, hostility, and threats from a society that treats you as less. Working with your nervous system won’t make these dynamics go away. Nor does it mean accepting them as okay. It takes a lot of healing before your body stops fighting you while you deal with them.

Why the nervous system is only part of the picture

In my early 20s, I could hardly remember what my body was responding to. My body remembered anyway. That’s an implicit memory: sensations or emotions far bigger than the moment, with no clear memory behind them. Most of my clients can’t remember the events, but their bodies and emotions react as if it were happening now.

Childhood trauma is rarely transformed by working with the nervous system alone. Many survivors I work with have parts that protected them as children: parts that talk them out of their boundaries, parts that are angry and fight, parts that yearn for connection at any cost. Read more: Signs of childhood trauma in adults.

When a survivor moves outside the window of tolerance, it’s usually a series of parts and not just one. I know this from my own healing. When I was shut down, I couldn’t reach my parts at all. Somatic work brought me back far enough to meet them. Parts work allowed me to heal the split between my emotional parts and my rational ones. I tell my clients the unfair part: only they can heal the wounds their parts carry, and they need safe enough people to do it. Read more: Parts work for adults with childhood trauma.

Healing the effects of childhood trauma

When I look back at myself in my early 20s, I understand things I couldn’t then. I did not know how deeply abuse had shaped my nervous system. I didn’t know why emotions felt so overwhelming, why I sometimes felt numb and disconnected, or why I occasionally dissociated.

Understanding trauma showed me that these were responses that helped me survive childhood abuse. None of them meant I was broken. But real safety took more than working with my nervous system. I chose to learn to set boundaries and be assertive. I accepted that safety isn’t fixed. It changes from moment to moment. And I trust that I can handle it when it isn’t. That’s where my freedom is.

Healing is possible. I’ve experienced it myself, and I’ve witnessed it in my clients. We can’t change the past. But we can change how we relate to ourselves and others. Read more: Healing childhood trauma as an adult.

If something in this sounded like you, and you want to heal, I’d like to hear from you. The first conversation is free.

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I offer online trauma recovery support for individuals in Canada and internationally. Explore my trauma recovery services or childhood trauma coaching for adults.

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