Q: I know that the study of neuroscience is intellectually fascinating, but how can it offer practical guidance when I’m working with a client with a trauma history?

A: As both a psychiatrist and a therapist some of the most challenging moments in my career have been with clients who suffer from complex trauma, disorganized attachment, and dissociative identity disorder. The extreme reactions associated with these diagnoses—including rage, cutting, suicidal ideation, panic, numbing, dissociation, and severe shame—have often left me frustrated, helpless, confused, and at times totally overwhelmed. But over the years, my knowledge of neuroscience has increased my ability to understand these reactions and how exactly to work with them while closely monitoring my own reactions. So while neuroscience isn’t a therapeutic approach in itself, it does help us understand why different interventions are required to address reactions that originate from different pathways in the brain.

To start, most extreme reactions resulting from trauma fall under one of two categories: sympathetic hyperarousal and parasympathetic blunting. Understanding what happens in the nervous system when clients experience sympathetic activation (a state of high physical energy, high emotion, and low ability to regulate and calm things) and parasympathetic blunting, or hypoarousal (characterized by low physical energy, low emotion, and low access to cognitive…