Trauma changes the brain's threat-detection system. The amygdala becomes hyperactive, the hippocampus (which contextualizes memory) shrinks under chronic stress, and the prefrontal cortex loses some of its ability to regulate fear responses. The result is a nervous system that behaves as if danger is still present, long after the event has ended.
This cascade explains the core symptoms: intrusive memories, exaggerated startle, avoidance, and sleep disruption. Neurochemical shifts in norepinephrine, serotonin, cortisol, and glutamate maintain the threat response and make everyday cues feel overwhelming. Addressing these biological changes often begins with psychiatric care for PTSD to assess symptom severity and coordinate medication and therapy.
Risk is not purely about the event itself. Genetics, prior trauma, coexisting depression or anxiety, and limited social support all influence who develops persistent symptoms. The VA National Center for PTSD emphasizes that recovery is possible with structured, evidence-based treatment tailored to the individual.
