How Trauma Affects the Brain

If you or someone you love has experienced an overwhelming life event, you may be left wondering: how does...

Trauma / PTSD Therapy
March 21, 2025

If you or someone you love has experienced an overwhelming life event, you may be left wondering: how does this trauma affect the brain?

When we go through situations that leave us feeling unsafe and powerless, the brain will try to send signals to help us reestablish security, typically through the "flight or fight" response.

However, when such reactions fail, there may be longer-term changes in specific regions of the brain--specifically the amygdala, hippocampus, medial prefrontal cortex, and dysregulated norepinephrine and cortisol levels.

Understanding Forms of Trauma

Traumatic events are not black-and-white.

There are many forms of trauma at varying degrees of intensity and long-term impact.  

However, there are specific instances that are commonly recognized to be traumatic.

This includes: various forms of abuse and violence such as sexual, domestic, mental/verbal, emotional, and religious; witnessing a violent crime or event; war and terrorism; bodily incapacitation such as losing a limb or becoming paralyzed; being kidnapped or taken hostage.

Some counselors also recognize the traumatic impacts of more common events such as betrayal/infidelity, car accidents, and sudden losses.

Diagram showing ways to look at Trauma

The Stress Response

Before addressing the specific ways trauma affects the brain, it is important to review the body's "stress response."

The body's nervous system can be divided into the central nervous system (CNS) and peripheral nervous system (PNS).

The PNS is divided further into the autonomic (ANS) and somatic nervous systems. The ANS includes the sympathetic, parasympathetic, and enteric nervous systems which interact with the hypothalamic-pituitary-adrenal (HPA) axis to regulate stress and physiological responses.

This interaction between the CNS, ANS, and HPA is what helps the body maintain homeostasis and adapt to its environment.

They do this through the chemical/hormonal mediators norepinephrine (noradrenaline), epinephrine (adrenaline), and cortisol.

Diagram showing Fight or Flight Response

Norepinephrine, Epinephrine, and Cortisol

When our brain's perceive a stressor, the CNS signals to the sympathetic nervous system to release norepinephrine and epinephrine into the bloodstream.

These chemicals attach to receptors in bodily tissues and trigger physiological responses intended to aid survival--i.e., to either fight or flee.

Such responses include increased blood pressure and heart rate, dilation of lung bronchi to increase oxygen output, and dilation of pupils.

Finally, after the initial activation of the stress response, the HPA releases cortisol into the bloodstream which triggers the release of stored glucose, fats, and amino acids to be used in sustaining the heightened physiological state.

Ultimately, all these reactions are geared towards survival, and once the threat is dealt with or escaped, the parasympathetic nervous system releases further chemical transmitters to bring the body back into equilibrium.

However, trauma is a unique type of stressor that may result in the PNS not being able to bring about normal homeostasis.

Dysregulated Stress Response

Traumatic events are unique stressors in that they are extreme, cumulative, and/or prolonged. Unlike short-term stressors such as, say, an upcoming exam or speaking in public, the continual or extreme activation of the stress response alters brain "circuits" or neural pathways.

This is particularly true when the trauma occurs in childhood, as the developing mind is highly elastic and susceptible to changes.

It is important to note that "trauma at different stages in life will presumably have different effects on brain development" (Bremner, 2006).

Studies done with animals showed that increased stress in infancy and youth, such as neglect or abuse, decreased cortisol receptors in the hippocampus, hypothalamus, and frontal cortex while increasing the levels of fluid activating the body's "stress response."

This means that trauma increases the brain's rate of reacting to stressors while decreasing its ability to eliminate the threat and/or calm down.

Cortisol plays a critical role not only in reacting to threats, but signaling to the body that the threat has been dealt with and it is okay to calm down.

This hyper-elevation of cortisol during traumatic experiences leads to lower levels in the future, while the brain is also becoming more sensitive to perceived threats and releasing norepinephrine/epinephrine.  

Trauma and Memory

Many trauma survivors develop Post-Traumatic Stress Disorder (PTSD).

PTSD manifests in specific symptoms, "including intrusive thoughts, hyperarousal, flashbacks, nightmares, and sleep disturbances, changes in memory and concentration, and startle responses" (Bremner 2006).  

Perhaps one of the most well-known symptoms of PTSD is memory alterations.

Victims often experience flashbacks that feel as if they are happening in the present moment, triggering the stress response to a non-existent threat.

According to various studies, it is unclear how the dysfunction with verbal declarative memory is related to trauma, for it seems to vary between single-event trauma and repeated trauma, as well as environmental factors and genetic predispositions.

Conclusion

The brain is a complex organ, constantly adapting to internal and external factors.

The body has a highly regulated "stress response" which activates upon perceiving a stressor, signaling the release of chemicals/neurotransmitters in preparation for fight or flight.

When we experience a traumatic event or series of events, the stress response can become dysregulated, with higher sensitivity to perceived threats, while having lower levels of cortisol to alleviate the stress.

Over time this can develop into PTSD or other cognitive disorders, further impacting memory and emotional regulation.

Resources

https://www.zrtlab.com/blog/archive/creating-balance-stress-response/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3181836/

https://pubmed.ncbi.nlm.nih.gov/8625891/

Author
Jennifer Luttman, LPC, ACS

I am a Licensed Professional Counselor, and owner of Overcomers Counseling. I'm dedicated to helping individuals find strength and healing through life’s challenges. With a deep understanding of mental health and years of professional experience, I specialize in fostering hope and resilience while equipping her clients with tools to thrive. Passionate about empowering others, she creates a safe, supportive space where everyone feels seen, valued, and capable of overcoming obstacles on their path to well-being.

Common Questions about Trauma / PTSD Therapy

How do I know if my communication style is assertive or aggressive?

Assertive communication involves expressing your needs and boundaries respectfully and clearly, while still considering the feelings and perspectives of others.Aggressive communication, on the other hand, may involve blame, criticism, or disrespect towards others.If you're unsure about your communication style, discuss it with your therapist, who can provide guidance and support.

How do I know if my insurance covers trauma-informed therapy?

To determine whether your insurance covers trauma-informed therapy, you can contact your insurance provider directly or review your benefits package for information about mental health coverage.

Additionally, when contacting potential therapists, ask if they accept your insurance plan.

What should I look for in a trauma-informed addiction treatment program?

Look for a program that emphasizes safety, trust, empowerment, collaboration, and the integration of trauma-specific interventions alongside evidence-based addiction treatment approaches.

How can I involve my loved ones in my self-care routine?

Communicate your self-care needs and goals with your loved ones, inviting them to participate in activities that promote well-being and relaxation.

Establish boundaries and request support as needed to ensure your self-care routine is respected and nurtured.

What if I don't know where to start with self-care?

Begin by reflecting on activities and practices that bring you joy, relaxation, or a sense of accomplishment.

Consult with your therapist, who can offer guidance and suggestions for incorporating self-care into your daily life and healing journey.

a therapist office

Is trauma counseling suitable for children and adolescents?

Yes. Trauma counseling can be adapted to suit individuals of all ages, including children and adolescents. It's important to address trauma in children as early as possible to prevent long-term effects on their mental health and development.