Exploring the Neurobiology of PTSD: A Glimpse into the Brain's Response to Trauma
- Students vs. Pandemics
- Apr 4
- 13 min read
Written by Courtney Coleman, Edited by Hannah Ryu, Han Trieu, and Gwendolyn Lee
Table of Contents
Post-Traumatic Stress Disorder (PTSD) is a complex condition that may occur after an individual has experienced or witnessed one or more traumatic events. In recent years, PTSD has become an increasingly urgent topic, particularly as the world grapples with the long-term psychological effects of the COVID-19 pandemic, ongoing global conflicts, and increasing exposure to violence and natural disasters (Abdalla et al., 2021; Abdalla et al., 2024; Doron Amsalem et al., 2025; Gissurardóttir et al., 2018; Motreff et al., 2020). The pandemic, in particular, has contributed to a rise in PTSD cases (Abdalla et al., 2024). Healthcare workers, survivors of severe illness, and those who have faced significant loss or isolation continue to struggle with long-term trauma (Fjone et al., 2024; Ouyang et al., 2022; Motreff et al., 2020; Murata et al., 2020). Consequently, it is crucial to understand the neurobiology of PTSD in order to comprehend how this condition affects individuals on a physiological level, which is an essential step toward developing effective treatments and providing support.
The Brain's Alarm System: Hyperarousal and the Amygdala
One of the regions of the brain that plays a central role in PTSD is the amygdala, which is an area of the brain that is crucial for processing emotions, particularly fear (Pitman et al., 2012). In individuals who have PTSD, the amygdala frequently demonstrates hyperactivity, and this results in the heightened emotional responses and increased sense of fear that are often experienced by those with this condition (Pitman et al., 2012). Additionally, this hyperarousal also contributes to symptoms such as hypervigilance, as well as an exaggerated startle response, and this heightened activity exhibited by the amygdala can perpetuate a persistent, inappropriate state of alertness, as well as provoke intense emotional responses, especially when the individual encounters a reminder of their traumatic event (Pitman et al., 2012).
The Role of the Prefrontal Cortex: Regulation and Inhibition
An additional section of the brain that is involved in PTSD is the prefrontal cortex (Alexandra Kredlow et al., 2022). This area of the brain is responsible both for making decisions and for emotional regulation (Alexandra Kredlow et al., 2022; Krawczyk, 2002). In those who have PTSD, the activity of the prefrontal cortex is significantly diminished, resulting in difficulties with controlling emotions (Alexandra Kredlow et al., 2022; Dahlgren et al., 2018). Consequently, this exacerbates the challenges an individual with PTSD experiences in regard to processing memories of their traumatic event(s), as well as maintaining emotional balance (Bremner, 2006; Brewin, 2015). Thus, the diminished regulatory control of the prefrontal cortex coupled with the heightened activity of the amygdala contributes to the emotional and behavioral symptoms that are characteristic of PTSD (Bremner, 2006; Brewin, 2015; Shin et al., 2005). Additionally, further research has demonstrated that functional abnormalities in the medial prefrontal cortex may exacerbate these difficulties (Bremner, 2006).
The Hippocampus and Memory: Reliving the Trauma
The hippocampus, a section of the brain that is crucial for memory consolidation, has been shown to become smaller in individuals with PTSD due to prolonged exposure to stress hormones (Bremner, 2006; Logue et al., 2018). As a result, this affects how memories are processed and stored, leading to the intrusive and recurrent memories that often affect individuals with PTSD, causing them to relive the traumatic event repeatedly, and contributing to the intrusive flashbacks and nightmares synonymous with the condition (Brewin, 2015; Francati et al., 2007). This can subsequently lead to difficulties in distinguishing between past and present experiences, further intensifying PTSD symptoms, findings that have been confirmed by neuroimaging studies that show a reduction in the volume of the hippocampus in those with PTSD (Brewin, 2015).
Neurotransmitters and PTSD
In addition to the various brain structures previously mentioned, neurotransmitters also play a crucial role in PTSD (Traina & Tuszyński, 2023). These chemical messengers facilitate communication between neurons and influence mood, cognition, and behavior (Traina & Tuszyński, 2023). The following are some key neurotransmitters involved in PTSD:
Norepinephrine (NE): Elevated NE levels are associated with hyperarousal symptoms in PTSD due to its release during stress (Bremner, 2006). This neurotransmitter activates the body’s “fight or flight” response, and in individuals with PTSD, this heightened NE activity contributes to anxiety, hypervigilance, and disturbances in sleep (Southwick et al., 1999; Wingenfeld et al., 2015).
Serotonin (5-HT): Serotonin is involved in mood regulation and emotional processing, and decreased serotonin levels have been observed in PTSD, which is thought to contribute to symptoms such as depression, irritability, and impaired impulse control (Hensler, 2010; Ogłodek, 2022). Consequently, medications that increase serotonin, such as selective serotonin reuptake inhibitors (SSRIs), are commonly used in PTSD treatment (Bremner, 2006; Ressler & Mayberg, 2007).
Gamma-Aminobutyric Acid (GABA): GABA is a neurotransmitter with an inhibitory effect that helps to regulate anxiety and stress responses (Traina & Tuszyński, 2023). In individuals who have PTSD, a dysfunction in GABA is thought to contribute to persistent feelings of fear, as well as an inability to relax (Michels et al., 2014; Mishra & Varma, 2023). As a result, medications that increase GABA activity, such as benzodiazepines, are sometimes prescribed as a PTSD treatment; however, their long-term use is considered to be controversial due to their potential side effects (U.S. Department of Veteran Affairs | PTSD: National Center for PTSD, n.d.; U.S. Department of Veteran Affairs | PTSD: National Center for PTSD, 2022).
Genetic Factors: The Intersection of Genes and Environment
In addition to the brain structures and neurotransmitters previously mentioned, certain genes, such as FKBP5 and CRHR1, also play a role in PTSD (Boscarino et al., 2012). Specifically, these genes are involved in the body's stress response, and they can interact with environmental factors, such as trauma exposure, to increase the risk of developing PTSD (Boscarino et al., 2012; Mahon et al., 2012; Pitman et al., 2012). Understanding these genetic components is vital for identifying individuals who may be more susceptible to PTSD and for tailoring interventions accordingly (Pitman et al., 2012). Thus, the interactions between having a genetic predisposition to PTSD with environmental triggers underscores the complexity of the condition and highlights the need for an approach that is based upon precision medicine (Pitman et al., 2012).
Treatment Approaches: From Medication to Psychotherapy
Addressing the neurobiology of PTSD is essential for treatment, and there are currently various approaches, including pharmacological options and psychotherapeutic interventions, aimed at improving symptoms and quality of life (U.S Department of Veterans Affairs, 2014). Some examples of medications that may be used in the treatment of PTSD are drugs that successfully target neurotransmitter systems to reduce anxiety and improve mood, as previously mentioned (Bremner, 2006; Ressler & Mayberg, 2007). Complementing the use of pharmacological interventions are psychotherapies, like cognitive-behavioral therapy (CBT) and exposure therapy, which focus on modifying thought patterns and reducing avoidance behaviors (American Psychiatric Association, 2013). Additionally, innovative treatments, such as eye movement desensitization and reprocessing (EMDR), as well as virtual reality exposure therapy, are also being explored to enhance therapeutic outcomes and are an interesting direction for future research (Rousseau et al., 2019).
Conclusion
Post-Traumatic Stress Disorder (PTSD) is a complex combination of the intricate landscape of the brain’s various structures, neurotransmitters, and various genetic factors (Alexandra Kredlow et al., 2022; Bremner, 2006; Logue et al., 2018; Pitman et al., 2012; Traina & Tuszyński, 2023). By exploring the neurobiology of PTSD, the unfortunate and profound impacts that trauma can have on the brain’s intricate architecture becomes evident; however, advancements in neuroscience and genetics hold substantial promise for more targeted and effective interventions (Boscarino et al., 2012; Mahon et al., 2012; Pitman et al., 2012). Thus, understanding the brain's response to trauma is crucial for developing more effective strategies for potentially preventing the development of PTSD, as well as for creating more effective treatments and improving the quality of life for those with this condition.
As the world continues to grapple with the psychological repercussions of the COVID-19 pandemic, ongoing global conflicts, and increasing exposure to traumatic events, gaining a more comprehensive understanding of PTSD is becoming progressively more vital (Abdalla et al., 2021; Abdalla et al., 2024; Doron Amsalem et al., 2025; Gissurardóttir et al., 2018; Motreff et al., 2020). Advancements in PTSD research continue to illuminate several unmet needs for new and additional therapeutic approaches, as well as early detection and personalized treatment strategies (Kravets et al., 2022; Morland et al., 2020; Nicholson et al., 2020; Torrisi et al., 2019). Additionally, bridging the gap between scientific discovery and practical application is essential for ensuring that individuals affected by PTSD receive timely and effective care (Committee on the Assessment of Ongoing Effects in the Treatment of Posttraumatic Stress Disorder; Institute of Medicine, 2012; Kravets et al., 2022; Morland et al., 2020; Nicholson et al., 2020; Torrisi et al., 2019). Consequently, advancing our awareness of PTSD can help individuals, healthcare providers, and policymakers work to expand access to mental health resources and reduce the stigma surrounding mental healthcare and trauma-related disorders. Therefore, by staying informed, advocating for accessible mental healthcare, and supporting ongoing research, we can shift the conversation from passive awareness into active intervention.
For those supporting someone with PTSD, fostering a sense of safety and trust is paramount. This can be achieved by providing a safe, nonjudgmental space to talk, practicing active listening, maintaining eye contact, using open-ended questions, and offering reassurance without pressuring them to share, which can help them feel heard and supported (U.S. Department of Veteran Affairs | PTSD: National Center for PTSD, 2025). In addition, it is equally as important to be aware of what actions to avoid, such as interrupting, dismissing their experiences, or imposing unsolicited advice, which can hinder their healing process (U.S. Department of Veteran Affairs | PTSD: National Center for PTSD, 2025). Furthermore, encouraging professional help, normalizing mental healthcare, and offering reassurance that support is available can make a meaningful difference in their recovery and well-being (U.S. Department of Veteran Affairs | PTSD: National Center for PTSD, 2025).
Through continued research support and advocacy, we can take meaningful steps toward improving outcomes for individuals impacted by PTSD, both at present and in the future. Ultimately, by fostering greater awareness, prioritizing accessible mental healthcare, and reducing the stigma around seeking help and trauma-related disorders, we can make significant strides in addressing PTSD, create a more compassionate and supportive environment, and ensure better outcomes for those who are affected.
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This post is not a substitute for professional advice. If you believe that you may be experiencing a medical or mental health emergency, please contact your primary care physician, or go to the nearest Emergency Room. Results from ongoing research is constantly evolving. This post contains information that was last updated on April 4, 2025.
Courtney Coleman is a graduate of Harvard University with a master's degree in biology, a member of the SvP Alumni Leadership Advisory Council, and Co-President of Students vs Pandemics.
Hannah Ryu is a senior at Wellesley College, majoring in Biochemistry and English, and pursuing the pre-med track. She is also a member of the SvP Alumni Leadership Advisory Council, and Co-President of Students vs Pandemics.
Han Trieu is a junior at UC San Diego, majoring in Psychology with an emphasis in Human Health and minoring in Biology. She is also a member of the SvP Alumni Leadership Advisory Council, and Vice President of Students vs Pandemics.
Gwendolyn Lee is an internal medicine resident at UCSF whose work centers on providing holistic healthcare to her patients, with a focus on preventive and lifestyle medicine in primary care. She is also the Co-Founder & Member of Board of Directors for Students vs Pandemics.