DID, PTSD & Dissociation Terms · Theories
Theory of Structural Dissociation (ANP & EP) and DID
In short: a theory that says trauma can keep a child’s personality from coming together as one, so it stays divided into parts: some that handle daily life, and some that hold the trauma.
What is it?
The Theory of Structural Dissociation of the Personality was developed by three researchers: Onno van der Hart, Ellert Nijenhuis, and Kathy Steele. They laid it out in their 2006 book, The Haunted Self. It builds on the much older ideas of Pierre Janet.
According to the theory, every child is born with built-in “systems” for different jobs. Some are for daily life, like playing, learning, and connecting with people. Others are for defense, like fighting, running, freezing, or giving in when there is danger.
Normally, as a child grows, these systems come together into one sense of self. The theory says that when a child goes through severe, repeated trauma, especially from caregivers, this coming-together doesn’t happen. The personality stays divided.
How does it work?
The theory names two kinds of parts:
- ANP (Apparently Normal Part): the part, or parts, that run everyday life: work, chores, taking care of others. They tend to avoid trauma memories so life can keep going. “Apparently” is used because things may look normal from the outside, even when they aren’t inside.
- EP (Emotional Part): the part, or parts, that hold the trauma: the fear, pain, body memories, and defense reactions.
The theory describes three levels:
- Primary: one ANP and one EP. The theory links this to simple PTSD.
- Secondary: one ANP and more than one EP. Linked to complex PTSD and some forms of OSDD.
- Tertiary: more than one ANP and more than one EP. Linked to DID.
How is it used?
Therapists who follow this theory usually work in phases: first safety and stabilization, then trauma memories, then bringing the parts together. A well-known workbook based on it is Coping with Trauma-Related Dissociation by Suzette Boon, Kathy Steele, and Onno van der Hart (2011).
What does the research say?
The theory’s authors describe it as a theory that is still being tested. Some brain-scan studies have looked at it:
- In a 2003 study, 11 women with DID listened to stories of their own trauma while in two different identity states: a “neutral” state, like an ANP, and a “trauma-related” state, like an EP. Their brains and bodies reacted differently in each state.
- In a 2012 study, women without DID who tried to act out the two states could not copy those brain and body patterns.
One of the theory’s authors, Ellert Nijenhuis, worked on these studies. Researchers who hold other views, such as the sociocognitive model, question whether trauma is the main cause of DID. See Do I Have DID? for more on that debate.
Structural Dissociation and DID
The treatment Guidelines for DID were first written in 1994, before this theory was published. The Guidelines credit Pierre Janet, in the late 1800s, with the idea of treating in phases.
You can read more about different models in A Survivor’s Guide to DID Models, and about the Guidelines in The “Standard of Care” for DID.
Related terms
A note about theories
The therapies and theories about trauma and DID are ideas that researchers are still studying and arguing about. None of them are proven facts. What works for one person may not work for another. Please take the time to read about any therapy yourself, ask questions, and decide what feels right for you.
Sources
Van der Hart, O., Nijenhuis, E. R. S., & Steele, K. (2006). The Haunted Self: Structural Dissociation and the Treatment of Chronic Traumatization. W. W. Norton.
Boon, S., Steele, K., & Van der Hart, O. (2011). Coping with Trauma-Related Dissociation: Skills Training for Patients and Therapists. W. W. Norton.
Van der Hart, O., Nijenhuis, E., Steele, K., & Brown, D. (2004). Trauma-related dissociation: Conceptual clarity lost and found. Australian and New Zealand Journal of Psychiatry, 38, 906–914.
Reinders, A. A. T. S., Nijenhuis, E. R. S., Paans, A. M. J., Korf, J., Willemsen, A. T. M., & den Boer, J. A. (2003). One brain, two selves. NeuroImage, 20(4), 2119–2125.
Reinders, A. A. T. S., Willemsen, A. T. M., Vos, H. P. J., den Boer, J. A., & Nijenhuis, E. R. S. (2012). Fact or factitious? A psychobiological study of authentic and simulated dissociative identity states. PLoS ONE, 7(6), e39279.
International Society for the Study of Trauma and Dissociation (2011). Guidelines for treating dissociative identity disorder in adults, third revision. Journal of Trauma & Dissociation, 12(2), 115–187.
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