Structural dissociation of the personality

Structural Dissociation of the Personality —Structural Dissociation of the Personality— is a theoretical-clinical model developed by Onno van der Hart, Ellert Nijenhuis, and Kathy Steele (2006), based on historical trauma research (Pierre Janet, Charles Myers from World War I) updated with contemporary neuroscience.

Central Premise: In the face of severe trauma, especially in childhood and particularly if prolonged, the psychic system fails to integrate the experience. Instead, it defensively fragments into parts with distinct functions. This fragmentation is not 'pathology' in a strict sense: it is an intelligent adaptation of the nervous system to impossible conditions.

The two classes of parts:

ANP — Apparently Normal Part: sustains daily life —work, social connections, adult functioning—. Its function is to keep the system running while avoiding trauma. The ANP has partial amnesia about the trauma or defensively denies it.

EP — Emotional Part: carries the trauma. It is fixated at the moment of trauma (same age, same emotions, same activated defenses: fight, flight, freeze, submission, attachment crying). When the EP erupts, the person experiences emotional flashbacks, hyperarousal, or severe dissociation.

Three levels (according to the degree of fragmentation): primary (classic PTSD, 1 ANP + 1 EP), secondary (C-PTSD, 1 ANP + several EPs), tertiary (DID, several ANPs + several EPs).

Clinical implication: Trauma therapy seeks progressive integration between the parts —not the elimination of some so that others dominate—. Slow, phase-by-phase work, with absolute priority given to stabilization before trauma processing.