When a traumatic event occurs, the brain processes the experience as a threat to survival. In this moment, the brain triggers a cascade of responses across different systems to deal with danger—responses that are crucial in the short term but can become harmful if they persist long after the event.
1. The Amygdala: The Alarm System
The amygdala is a part of the brain responsible for detecting danger and activating the body’s stress response. When a traumatic event happens, the amygdala sends a distress signal to mobilise the “fight, flight, or freeze” reaction. This prepares the individual to confront or escape the perceived threat.
What Happens:
In trauma survivors, the amygdala can remain overactive, perceiving threats in everyday situations even when no real danger exists. This can lead to hypervigilance, anxiety, or difficulty calming down.
2. The Prefrontal Cortex: The Rational Thinker
The prefrontal cortex helps regulate decision-making, reasoning, and emotional control. It usually works to balance the amygdala’s fear signals with a rational assessment of the situation.
What Happens:
Trauma can reduce the activity of the prefrontal cortex, making it harder to differentiate between actual danger and false alarms. As a result, emotional reactions might feel overwhelming or disproportionate.
3. The Hippocampus: The Memory Keeper
The hippocampus plays a vital role in processing and storing memories, along with distinguishing between past and present experiences.
What Happens:
In traumatised individuals, the hippocampus can shrink or become underactive. This can lead to difficulty placing traumatic events in the past, causing flashbacks or intrusive memories to feel vivid and immediate.
The Role of Stress Hormones
Trauma deeply affects the body’s hormonal system, particularly cortisol and adrenaline. These hormones are part of the body’s natural “stress response,” helping it react to danger by increasing heart rate, blood pressure, and energy levels.
1. Cortisol: The Stress Hormone
Cortisol is released during times of stress to help the body focus on dealing with immediate threats.
What Happens:
Chronic trauma often results in either overproduction or underproduction of cortisol, leading to problems such as:
- Overactive stress responses, where the body feels constantly on high alert.
- Difficulty relaxing, sleeping, or feeling safe.
- Fatigue and immune system dysfunction from long-term cortisol dysregulation.
2. Adrenaline: The Emergency Hormone
Adrenaline fuels the “fight or flight” response by increasing oxygen and energy flow to the body.
What Happens:
Following trauma, adrenaline levels may remain elevated. This can cause symptoms of hyperarousal, such as an inability to focus, a heightened startle response, or physical restlessness.
Trauma and the Body
Trauma is not just a mental health issue—it is an example of the undeniable connection between the mind and body. Prolonged exposure to trauma or stress can lead to lasting physical symptoms, as unprocessed trauma disrupts the body’s physiological balance.
1. The Autonomic Nervous System
The autonomic nervous system (ANS) governs involuntary body functions like heart rate, breathing, and digestion. It consists of:
- The sympathetic nervous system (activates “fight or flight”).
- The parasympathetic nervous system (restores “rest and digest”).
In healthy individuals, these systems work in harmony. Trauma survivors, however, may experience an overactive sympathetic system, leaving them “stuck” in a state of hypervigilance. Conversely, some individuals may feel immobilised, unable to engage emotionally or physically—this is known as the “freeze” response.
2. Somatic Symptoms
Trauma often manifests physically in the form of somatic symptoms, even when no medical cause is present. Common examples include:
- Chronic pain or muscle tension (e.g., neck, back, or jaw pain).
- Gastrointestinal symptoms (e.g., irritable bowel syndrome, nausea).
- Headaches or migraines.
- Fatigue or insomnia.
The body essentially “stores” trauma that has not been resolved, leading to physical discomfort and health issues.
3. The Immune System
Chronic stress caused by trauma can weaken the immune system, increasing susceptibility to illnesses. Survivors of trauma may also experience heightened inflammation levels in the body, contributing to conditions like heart disease, arthritis, or diabetes.
Trauma and Brain Plasticity: The Potential for Healing
One of the most hopeful discoveries in neuroscience is evidence of neuroplasticity, which refers to the brain’s ability to reorganise itself by forming new neural connections. While trauma can alter brain processes, resilience and recovery can help “rewire” the brain toward healing.
How It Works:
Through consistent therapeutic interventions, self-care, and support systems, individuals can strengthen their prefrontal cortex, regulate the amygdala’s signals, and help the hippocampus process memories appropriately.
Example:
Practising mindfulness or physical grounding techniques can activate the parasympathetic nervous system, calming the stress response and reinforcing healthy brain circuits.
Trauma Recovery: A Biological Perspective
Understanding the science behind trauma enables individuals to approach recovery with compassion for themselves and others. Healing often involves working directly with the systems affected by trauma:
Evidence-Based Approaches
- Trauma-Focused Therapy: Methods like Cognitive Behavioural Therapy (CBT) and Eye Movement Desensitisation and Reprocessing (EMDR) help reorganise traumatic memories in a way that reduces distress.
- Somatic Therapies: Grounded in the understanding of trauma’s effect on the body, therapies like Somatic Experiencing and trauma-informed yoga help release stored tension and promote regulation of the nervous system.
- Medication: Prescriptions for anxiety, depression, or sleep disturbances can regulate imbalances caused by trauma.
Self-Care Practices
- Mindfulness and Meditation: These techniques directly calm the nervous system, reducing hyperarousal.
- Exercise: Regular physical movement helps discharge pent-up energy from the body and boosts mood.
- Social Connections: Strong, supportive relationships contribute to the healing of trauma-affected brain circuits.
Final Thoughts
Trauma creates profound changes in the brain and body, shaping how individuals perceive and respond to the world. While this can feel overwhelming, the science of trauma provides hope and clarity. By understanding how trauma affects key systems—from the amygdala to stress hormones—individuals can take informed steps toward healing and resilience.
Most importantly, recovery is possible. Through therapy, self-awareness, and supportive environments, the brain’s plasticity allows individuals not only to heal but to grow. Just as the effects of trauma are not permanent, neither is the pain it brings. Healing is a journey—and the body and brain have the remarkable capacity to repair and recover.
