How Trauma and PTSD Change the Brain

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Traumatic experiences like abuse, assault, tragedy, or witnessing violence can leave people feeling constantly on edge. And PTSD can impact your emotions, your stability, and your relationships. Trauma can also have an impact on physical and mental health. 

And these are really common experiences for many people. And they’re due in part to four ways that your brain changes after experiencing trauma. 

But the good news is that when you understand how trauma impacts the brain, these symptoms can often be reversed. You can learn to heal.

So quick review: when you experience something threatening or dangerous or just witness something happening to someone else, your brain activates the fight/flight/freeze response — essentially the survival mode — in the reptile part of your brain. 

This response helps keep you safe. It shuts down thinking, it releases a surge of hormones like cortisol and adrenaline, and it sends blood to the big muscles so you can fight or run away. This gets your heart pounding. It speeds up your breathing. And all of this is so that you’re prepared to take physical action to stay safe. 

And then after the threat has passed, your nervous system should go back into restorative mode, the rest-and-digest mode. 

But with PTSD, something interferes with your ability to feel safe. Your brain and your body stay stuck in this mode, so even when you’re safe, your brain and your body stay tense. They’re on high alert. And you don’t ever or don’t often revert back to that restorative mode. 

So when trapped in a constant trauma response, people with PTSD experience four types of difficult symptoms. These include: 

  • Painful thoughts (which is like upsetting memories, flashbacks, and memory loss)
  • Intense emotions (feeling helpless, anxious, ashamed, scared, jumpy, angry, feeling blame or persistent negativity, or just feeling numb) 
  • Bodily changes (so these include increased heart rate, feeling jittery or on edge, startling easily, unexpected rage or tears, short and shallow breathing, panic attacks, insomnia, or nightmares)
  • Behavioral changes (so this is usually avoidance of anything related to the trauma or its memories) 

Now, these symptoms show up because after experiencing trauma, your brain changes on a physical level. Now this isn’t simply damage as people would perhaps think, but it’s your brain adapting to the experience that the world isn’t safe. And in my opinion, it’s your brain taking measures to help you avoid future dangers. So essentially your brain makes you more danger-avoidant. 

Your brain is super moldable. It adapts and it rewires depending on what we experience and how we use our brain. 

So when we experience trauma, here are four ways that the brain changes or adapts after that experience. 

4 Ways the Brain Changes after Trauma

1. The Amygdala

So first, you need to know about the amygdala. This is an area of the brain that scans for threats, and it connects memories and emotions. So this is kind of like the smoke alarm of the brain. And after trauma the amygdala becomes much more active. It becomes much more sensitive and more likely to alert, to turn on that alarm when it perceives a threat. 

Survivors become less tolerant of stress, and little things make them feel more anxious. So common things like loud noises, people entering a room from behind, or seeing someone who reminds them of an aggressor, these can all trigger that threat response, even when the loud noise is just fireworks or when that person with a beard is actually just a waiter. 

I’ve had clients who felt triggered by grasshoppers or radiators. And both of these things are actually safe, but the amygdala associates them with trauma and then sets off that red alert. 

So to summarize: with PTSD the amygdala becomes more sensitive. 

2. The Hippocampus

Second: brain scans indicate that after trauma, the hippocampus shrinks. So the hippocampus is the part of the brain that processes emotions and memories. After trauma, stress hormones essentially kill off cells in the hippocampus, making it less effective at processing emotions. 

This also makes it hard for the brain to distinguish between the past and the present. So this is essentially what a flashback is — it’s your brain experiencing a memory that feels like it’s happening right now. 

People who’ve experienced trauma, they may have missing memories, fragmented memories, or painful memories that pop up when they don’t want them. And when these memories pop up, they re-trigger the amygdala. 

So essentially the amygdala perceives the memories as a new threat and sends off that alarm. That restarts that trauma cycle, that whole flooding of the fight/flight/freeze response and all those physical changes and the stress hormones and all of that. 

Now, these changes to the hippocampus can also contribute to short-term memory loss. But the connection between the hippocampus and the amygdala gets stronger. Like, these two love talking to each other now. And so essentially this maintains that fear response over time. Even if you can’t remember the traumatic event, your smoke alarm is still going to blare with the slightest trigger. 

3. The Prefrontal Cortex

Number three: the prefrontal cortex shrinks. So this is the part of the brain that essentially handles higher-order thinking and planning, rational thought, and language — things like that. This part of the brain becomes disrupted by constantly reverting back to that fight/flight/freeze part of the brain or the reptile part of the brain. 

So when you’re stuck in fight/flight/freeze or hypervigilance, the thinking part of the brain gets turned down. And the way that neuroplasticity works is the more we use a part of the brain the more pathways grow there, but the less we use a part of the brain those pathways get trimmed. 

So when we can’t use reason to think through our traumatic memories or sensations, then it makes it hard for us to override that danger signal that the amygdala and hippocampus are sending, and it makes it harder to remind ourselves that the danger is not real. 

So because that prefrontal cortex has shrunk a little bit, it makes it harder to process through those memories, it makes it harder to speak about what happened, it makes it harder to think clearly and rationally. And you can see how a person can get trapped in a loop of trauma if they don’t get treatment. So these symptoms just make it harder and harder to escape the cycle of PTSD. 

4. The Nervous System after PTSD

Number four: the last way your brain is impacted is really through the broader nervous system. So this constant flooding with stress hormones keeps the body locked in an activated sympathetic state or the fight/flight/freeze state. It’s also known as hyperarousal. 

So you feel constantly on edge, you feel jittery, you feel stressed out – until you get exhausted. Then you have adrenal fatigue, right? You shut down and you feel depressed. 

So being stuck in this state of an overactive dysregulated nervous system leads to a lot of strain on the body, and that can contribute to chronic illnesses like autoimmune disorders, low functioning of the immune system, diabetes, obesity, muscle tension, chronic pain, and problems with like sleep and the gut and and your heart health. 

Healing and Hope with PTSD

So those are the four ways that trauma impacts your brain and nervous system in general. But just like how your brain changed in response to trauma, it can heal too. And this is called neuroplasticity. 

So your brain adapted the trauma response as a functional way to deal with real threats and dangers. Your brain’s not out to get you. But it also has a built-in ability to change in response to healing and perceived safety. 

So the amygdala can learn to chill out. The hippocampus can relearn how to process emotions. And your nervous system can strengthen its ability to revert back to that parasympathetic or that rest-and-digest response. We can target these structures in the brain and in the body through cognitive work and through body-based work. 

So a couple of the ways that we can do this are through yoga, mindfulness, writing exercises. So just think of this: you’re having a trauma response, you’re having these big, intense emotions, and you sit down and you make yourself write about it. 

That’s turning on the prefrontal cortex. That’s clarifying that in the present moment you are safe. It’s helping your hippocampus process through memories, and that sends a message to your amygdala that you’re actually safe. 

So something as simple as a writing exercise can help rewire your brain from that trauma. 

More types of treatments include CBT, EMDR, somatic experience. These are all treatments that help your brain and body rewire and restore your inner sense of safety and clarity. 

Now, there’s a lot of studies out there that show that your brain can rewire like this, but let me give you one example. Research using MRI scans of the brain shows that mindfulness practice is correlated with growth in the hippocampus and shrinking of the amygdala. So essentially it reverses the effects of trauma. 

I teach a bunch of these skills on my channel, so check out my healing trauma playlist if you’d like to learn more. Or you can check out my free course, Grounding Skills for Anxiety and Trauma. The link’s in the description below. And in an upcoming video, we’re going to talk about how being transformed by trauma can lead to good things. 

So please remember there’s always room for growth and healing and change, and it just comes from the tiny little baby steps that you can take. 

So thank you for watching. I love you all. And take care.

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