Trauma can alter brain function, leading to increased vigilance and defensive behavior.

“I think the helpful definition is something that rises to the magnitude of really changing us and something that we can see both in how we behave. We can see it in mood, anxiety, behavior, sleep, physical health. So we can identify it and we can also see it in brain changes. So the fact that we become, say more hypervigilant, right? More vigilant, and then we can see that different parts of the brain are more active.”