**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.
Evidence and contemporary voices
The Structural Dissociation of the Personality (SDP) model, proposed by Onno van der Hart, Ellert R. S. Nijenhuis, and Kathy Steele, describes how chronic and severe trauma during critical developmental periods generates a fragmentation of the personality into two types of parts: Apparently Normal Parts (ANP), oriented toward daily action and inhibiting traumatic perceptions, and Emotional Parts (EP), which encapsulate traumatic experiences with functions like survival, attachment, or avoidance. This framework integrates structural trauma theory with dissociation as a primary adaptive defense (van der Hart et al., 2006). Clinical research in institutions such as the Trauma Clinic Amsterdam and the Complex Trauma Unit at McLean Hospital has validated its utility in treating complex post-traumatic stress disorder (C-PTSD) and dissociative disorders, with phased treatment protocols that prioritize stabilization, trauma processing, and integration (Boon et al., 2011; Nijenhuis, 2017). Empirical studies, such as those by Lanius et al. (2010) at the University of Western Ontario, confirm neurobiological patterns of dissociation in fMRI scans, showing amygdalar hyperactivity in EPs and prefrontal deactivation in ANPs during traumatic exposure.
Verifiable quotes
- "Structural dissociation of the personality refers to the division into ANP and EP as a response to unintegrated trauma." — Onno van der Hart, Ellert R. S. Nijenhuis, and Kathy Steele, The Haunted Self: Structural Dissociation and the Treatment of Chronic Traumatization (2006, p. 137).
- "ANPs avoid trauma while PPs keep it alive in the present." — Ellert R. S. Nijenhuis, The Trinity of Trauma: Ignorance, Fragility, and Control (2015, p. 45).
Researchers and Key Figures
- Onno van der Hart — Trauma Clinic Amsterdam — theory of structural dissociation and chronic trauma
- Ellert R. S. Nijenhuis — SHO Mental Health — neurobiology of trauma and the DSP model
- Kathy Steele — The Center for Attachment & Trauma — phased treatment of dissociation
- Ruth A. Lanius — University of Western Ontario — neuroimaging of traumatic dissociation
Auditable Sources
Additional research generated with consultation of academic sources (Perplexity Sonar Pro). Citations and URLs are the responsibility of their original source; verify before formally citing.
Bibliography
- The Haunted Self — Structural Dissociation and the Treatment of Chronic Traumatization — Onno van der Hart, Ellert Nijenhuis, Kathy Steele. Desclée de Brouwer, 2008.
- Healing the Fragmented Selves of Trauma Survivors — Janina Fisher. Eleftheria, 2017.
These books are in the reference library that nourishes Constelando el Origen.
Related Terms
Onno van der Hart
Dutch psychologist (1941-). Pioneer in the study of traumatic dissociation. Co-author with Nijenhuis and Steele of the Theory of Structural Dissociation of the Personality (TSDP).
View profileComplex Trauma (C-PTSD)
Disorder formulated by Judith Herman (1992): trauma resulting from prolonged exposure to abuse, neglect, or severe dysfunctional relationships, especially in childhood. Different from classic PTSD.
View profileJanina Fisher
Contemporary American psychologist. Specialist in dissociation and complex trauma. Integrates IFS, sensorimotor, and attachment theory for work with survivors of severe trauma.
View profileJudith Herman
American psychiatrist (1942-). Pioneer in the field of trauma. Formulated the concept of C-PTSD (complex trauma) in her foundational book 'Trauma and Recovery' (1992).
View profileIFS — Internal Family Systems
Richard Schwartz's therapeutic model: working with the psyche's internal 'parts' as if they were an inner family, mediated by the adult Self.
View detailsA session that names what hurts
If you recognize this dynamic in your own history, a Family Constellation can reveal where it comes from and what movement can bring order to it. Daniela respectfully accompanies each case.
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