A caregiver and a brain injury survivor sit together at sunset, symbolizing connection, trauma recovery, and hope after PTSD and cPTSD

When the Brain Doesn’t Remember, but the Body Still Does: Understanding PTSD and cPTSD After Brain Injury By Heather Robbins | The Nesting Journal – Robbins Nest Alliance

The Hidden Collision Between Trauma and the Brain

People often see the physical side of a brain injury, the memory loss, the tremors, the slurred speech. What they don’t see are the invisible aftershocks: the panic that surfaces out of nowhere, the flash of anger without warning, or the deep emotional numbness that follows.

For many survivors, those reactions aren’t “just” personality changes or mood swings. They’re signs of post-traumatic stress disorder (PTSD) or complex PTSD (cPTSD) layered on top of an already-injured brain. And because the two share so many overlapping symptoms, they’re often misunderstood even by medical professionals.

According to research from the National Institutes of Health, up to 30% of people with a traumatic brain injury (TBI) also meet criteria for PTSD, though the number is likely higher among veterans and domestic violence survivors.[1] The result is a condition that’s not just neurological or psychological, it’s both.

PTSD vs. Complex PTSD: The Basics

PTSD typically develops after a single, overwhelming event like a car crash, an explosion, or an assault. The brain can’t fully process the trauma, so it stays stuck in a constant state of alarm.

Complex PTSD (cPTSD) develops after repeated or long-term trauma. Survivors of domestic violence, emotional abuse, combat, or institutional trauma (like in sports or the military) often fall into this category. The body learns to live in survival mode, even after the threat is gone.

Shared symptoms include:

  • Flashbacks, nightmares, or intrusive thoughts

  • Emotional detachment or numbness

  • Irritability, anger, or hypervigilance

cPTSD adds deeper layers:

  • Intense emotional swings that feel uncontrollable

  • Persistent shame or feelings of worthlessness

  • Struggles to trust or maintain relationships

When combined with TBI, these symptoms can blur together. Memory gaps might make trauma hard to recall consciously, but the body still remembers.

How the Brain and Trauma Interact

Both PTSD and brain injury alter the brain’s wiring. In PTSD, the amygdala (the brain’s fear center) becomes overactive, the prefrontal cortex (logic and regulation) goes offline, and the hippocampus (memory center) shrinks or misfires.[2]

TBI can cause the same disruptions. The difference is that with TBI, the damage is physical, neurons and pathways have been stretched, bruised, or destroyed. In PTSD, it’s functional circuits become trapped in feedback loops of fear and hyperarousal.

When both occur together, the result is a perfect storm:

  • The brain struggles to separate danger from safety.

  • Emotional control becomes unpredictable.

  • Fatigue and cognitive overload make recovery slower.

This is why survivors may feel “wired and tired” all the time unable to rest, but too exhausted to function.

What It Looks Like in Everyday Life

For families and caregivers, this overlap can be confusing. A loved one might look calm one moment and then erupt in anger or shut down the next.

Common patterns include:

  • Extreme sensitivity to noise or movement

  • Sudden panic or freezing without clear reason

  • Emotional withdrawal or disinterest in loved ones

  • Forgetting key details but remembering the feeling of fear

  • Trouble sleeping, startle responses, or intense dreams

These reactions aren’t character flaws—they’re the body’s protective mechanisms misfiring. The nervous system is still trying to survive an old threat while living in a new reality.

Why Diagnosis Often Gets Missed

Clinicians often focus on the visible: balance, speech, or coordination. Emotional and behavioral changes are sometimes written off as “just part of the brain injury.”

In the military and sports worlds, stigma plays a huge role. Many veterans and athletes fear being seen as weak or unstable. Others genuinely don’t realize their emotional volatility and memory problems could be connected to trauma.[3]

Domestic violence survivors face a different barrier, many have been conditioned to minimize their pain or question their own perceptions. As a result, trauma often goes untreated for years.

Research from the U.S. Department of Veterans Affairs shows that without trauma-informed screening, up to 40% of PTSD cases in brain-injury survivors remain undiagnosed.[4]

The Science of Healing

The good news: recovery is possible. Both TBI and PTSD involve neuroplasticity the brain’s ability to rewire itself. Healing comes through safety, consistency, and integrated treatment that respects both the mind and the body.

Approaches that show promise include:

  • Trauma-informed therapy (such as EMDR or somatic experiencing)

  • Cognitive rehabilitation paired with psychotherapy

  • Mind-body practices like breathing, yoga, and grounding

  • Caregiver education to understand triggers and prevent retraumatization

Rehabilitation that ignores trauma can stall progress. Conversely, trauma therapy that overlooks brain injury can overload the nervous system. The best outcomes come from addressing both, slowly and compassionately.

A Message for Caregivers

If you’re caring for someone with a brain injury and notice emotional volatility, memory gaps, or extreme reactions, trust your instincts. You’re not imagining it, and they’re not choosing it.

You can support healing by:

  • Keeping routines predictable

  • Encouraging rest and safe connection

  • Avoiding confrontation during emotional spikes

  • Seeking professionals trained in both trauma and brain injury

Healing isn’t linear, but it is possible. With the right support, survivors can rebuild identity, restore connection, and begin to feel safe again inside their own minds.

References

[1] National Library of Medicine (2023). Prevalence of PTSD After Traumatic Brain Injury: A Systematic Review.
[2] Harvard Medical School (2022). Neurobiology of Trauma and Memory.
[3] U.S. Department of Veterans Affairs (2024). PTSD and TBI in Military Populations.
[4] Cleveland Clinic (2024). Complex PTSD and Chronic Brain Trauma: Overlapping Symptoms and Pathways to Care.

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