Bruce Perry

It made sense: a person with an overactive stress system would pay close attention to the faces of people like teachers and classmates, where threat might lurk, but not to benign things like classroom lessons.

Dissociation is a very primitive reaction: the earliest life forms (and the youngest members of higher species) can rarely escape dire situations under their own steam. Their only possible response to being attacked or hurt, then, is essentially to curl up, to make themselves as small as possible, to cry for help and hope for a miracle.

During dissociation, the brain prepares the body for injury. Blood is shunted away from the limbs and the heart rate slows to reduce blood loss from wounds. A flood of endogenous opioids—the brain’s natural heroin-like substances—is released, killing pain, producing calm and a sense of psychological distance from what is happening.

As one family therapist famously put it, we tend to prefer the “certainty of misery to the misery of uncertainty.”