Trauma is defined not by the event but by the organism’s response to it. A traumatic experience is one that overwhelms the nervous system’s capacity to process, integrate, and resolve the threat. The same event — a car accident, an assault, a natural disaster — may be traumatic for one person and not another, depending on their resources, support, history, and nervous system capacity at the time.
What makes trauma pathological is the failure of resolution. In a normal threat response, the autonomic nervous system mobilizes for defense (fight or flight), the threat passes, and the system discharges the mobilization energy and returns to baseline. In trauma, this cycle does not complete. The defensive energy remains stored in the body — the person remains physiologically in the threat state even after the threat has passed. This is Somatic Experiencing’s central framework: trauma is a physiological event, and it must be resolved physiologically.
Post-traumatic stress disorder (PTSD) is the clinical syndrome that results: re-experiencing (intrusive memories, flashbacks), avoidance (of reminders and of emotional engagement), hyperarousal (the nervous system stuck in chronic threat-detection), and negative alterations in cognition and mood.
Complex trauma (developmental trauma) results from prolonged, repeated traumatic experiences, especially during childhood within caregiving relationships. It alters not just memory but the developing nervous system itself — stress-response architecture, attachment patterns, affect regulation capacity, and physical health across the lifespan. Adverse childhood experiences (ACEs) research demonstrates dose-response relationships between childhood adversity and adult disease.
Trauma history is a significant factor in chronic pain: ACEs alter stress-axis regulation, immune function, and pain processing, contributing to conditions the biomedical model cannot explain through tissue damage alone.
Related terms
- Affect — the felt dimension of traumatic states
- Attachment — early relational patterns shaped by traumatic and non-traumatic caregiving
- Defense Mechanism — psychological processes that manage traumatic material
- Somatic Experiencing — resolving trauma through the autonomic nervous system
- The Biopsychosocial Model of Pain — trauma as a factor in chronic pain
- Disability Justice — structural conditions that produce and compound trauma