How Trauma Affects the Brain and Body
Trauma is more than a psychological event - it’s a whole-body experience. When someone endures a traumatic event, the impact can go far beyond the immediate emotional aftermath. It rewires the brain’s pathways, disrupts the body’s systems, and alters how we respond to stress, relationships, and even ourselves. Understanding how trauma affects the brain and body is essential for both survivors and the professionals who support them.
What Is Trauma?
Trauma is the emotional and physiological response to a deeply distressing or disturbing event. It may stem from a single incident like an accident, or from prolonged exposure to stressors such as abuse, neglect, or systemic oppression. While the causes of trauma vary, the body’s response tends to follow similar patterns.
The Brain Under Siege
Trauma affects key regions of the brain responsible for memory, emotion regulation, and survival instincts. The three most impacted areas are the amygdala, hippocampus, and prefrontal cortex.
Amygdala: The Alarm System
The amygdala is the brain's threat detection system. After trauma, it becomes hypersensitive, triggering the "fight, flight, freeze, or fawn" response even in the absence of real danger. This heightened alertness can lead to chronic anxiety, hypervigilance, and intense emotional reactions to reminders of the trauma (also called “triggers”).
Hippocampus: Memory and Context
The hippocampus helps encode and organize memories. This region may shrink during a traumatic event since memories aren’t necessary for survival, leading to fragmented or disorganized memories of the event. This is why trauma survivors may have flashbacks, nightmares, or confusion about the sequence of events. Some survivors may even have gaps of missing memory altogether. Additionally, the hippocampus's reduced ability to differentiate past from present makes triggers especially destabilizing.
Prefrontal Cortex: Executive Function
The prefrontal cortex governs rational thought, decision-making, and emotional regulation. Under trauma, this region can go offline, especially during stress. That’s why trauma survivors may struggle to manage their emotions, make rational decisions, or feel in control of their reactions. Essentially, the brain gets stuck in survival mode.
Trauma’s Toll on the Body
The body doesn’t just store trauma metaphorically, it holds it biologically. The autonomic nervous system (ANS), hormonal systems, and immune function are all affected.
Nervous System Dysregulation
Trauma dysregulates the ANS, which controls automatic functions like heart rate and digestion. Survivors may shift between hyperarousal (anxiety, panic, racing thoughts, upset stomach) and hypoarousal (numbness, dissociation, fatigue). This makes it difficult to feel safe or grounded, even in calm environments.
Chronic Stress Hormones
When the body perceives danger, it releases cortisol and adrenaline. In trauma survivors, these stress hormones can remain elevated long after the threat is gone. Chronic overexposure can impair memory, weaken immunity, and increase the risk of conditions like heart disease, diabetes, and chronic pain.
Somatic Symptoms
Trauma can manifest physically as headaches, gastrointestinal issues, muscle tension, fatigue, and autoimmune disorders. These symptoms often persist without clear medical causes, frustrating both patients and providers who may not recognize the trauma connection.
Healing Is Possible
Although trauma causes real, measurable changes in the brain and body, healing is possible. Treatments like trauma-informed therapy, EMDR (Eye Movement Desensitization and Reprocessing), TF-CBT (Trauma-Focused Cognitive Behavioral Therapy, somatic experiencing, and mindfulness-based practices help rewire the nervous system and restore a sense of safety and control.
Importantly, healing is not just cognitive, it must also involve the body. Movement, breathing, creative expression, and connection to others all play vital roles in recovery. Trauma thrives in isolation, but healing happens in safe, supportive environments where individuals can rebuild trust - in themselves, in others, and in their bodies.
Conclusion
Trauma is not “just in your head” or someone being “sensitive” or “weak”. It is very real and shapes the very architecture of your brain and the function of your body. By understanding the profound ways trauma influences our systems, we can approach ourselves and others with more compassion, patience, and informed care. Healing may not be linear, but it is absolutely possible.
-Ciera Canaday, LCSW and Clinical Director