Understanding Dissociation: A Clinical and Human Perspective

As a mental health clinician, I rely on the Diagnostic and Statistical Manual of Mental Disorders (DSM), published by the American Psychiatric Association, to guide diagnosis and inform treatment planning (American Psychiatric Association, 2013). The DSM provides a shared framework that allows clinicians to communicate clearly, apply consistent diagnostic criteria, and make informed decisions about care, research, and insurance coverage.

This kind of structure matters. It ensures that mental health conditions are understood using a common language, that treatment approaches are grounded in established knowledge, and that individuals can access the services they need. While no manual can fully capture the complexity of human experience, it offers an important foundation for clinical work.

What Is Dissociation?

Dissociation, as defined in the DSM-5, involves a disruption in the normal integration of consciousness, memory, identity, emotion, perception, body awareness, motor control, and behavior (American Psychiatric Association, 2013).

In lived experience, this can feel like a kind of disconnection, from oneself, from one’s surroundings, or from one’s sense of continuity over time.

These experiences are typically involuntary and can be disruptive, and they are often linked to psychological trauma (Spiegel et al., 2013). Importantly, dissociation is characterized by a detachment from reality, rather than a distortion of reality, which distinguishes it from psychotic processes (Lynn et al., 2022).

Dissociation Exists on a Spectrum

Not all dissociation is severe or pathological. In fact, many forms are quite common and even adaptive in certain contexts (Boyer et al., 2022).

At the milder end, dissociation might look like becoming deeply absorbed in a book or experiencing “highway hypnosis” during a long drive. These are everyday examples of attention narrowing and temporary disengagement.

More complex forms include:

• Depersonalization, or feeling disconnected from one’s body, as though observing oneself from the outside

• Derealization where the external world feels unreal, distant, or dreamlike

• Dissociative amnesia, involving gaps in memory for important personal experiences or events

Understanding this spectrum can help normalize some experiences while also recognizing when dissociation becomes clinically significant.

Dissociation and Dissociative Identity Disorder (DID)

Dissociation is central to understanding Dissociative Identity Disorder (DID).

When a person is exposed to overwhelming or repeated trauma, particularly during early development, the mind may adapt by compartmentalizing distressing experiences. This allows the individual to function without being fully overwhelmed by what has happened (Lynn et al., 2022).

Over time, these compartments can become more distinct and organized. In DID, they may be experienced as different parts of the self, sometimes referred to as “alters.” These parts can carry different emotions, roles, memories, and perspectives, and may even differ in age, gender, or needs (Ozturk & Şar, 2016).

Another key feature is switching, or shifts between parts. These shifts are typically involuntary and are often accompanied by gaps in memory for what occurred while another part was in control (Elzinga et al., 2003). Switching is strongly associated with trauma (Barlow & Chu, 2014), and research suggests it may involve activation in brain regions related to sensory processing, reward, and executive functioning (Savoy et al., 2012).

The Window of Tolerance

The concept of the “window of tolerance,” developed by Daniel Siegel, describes the range of emotional arousal in which a person can remain regulated, feel safe, and effectively process experiences (Siegel, 1999).

For individuals with trauma histories, including those with DID, this window is often narrower. This means the nervous system can more easily become overwhelmed or shut down.

When someone moves outside their window of tolerance, it typically happens in one of two directions:

Hyperarousal (fight or flight) involves heightened activation of the nervous system and may include anxiety, panic, anger, or hypervigilance. In individuals with DID, certain parts may come forward to manage or cope with these intense states (Purcell et al., 2024).

Hypoarousal (freeze or shutdown) involves a drop in activation and may include numbness, disconnection, fatigue, or dissociation. During these states, dissociative defenses often become more prominent, and parts may take over to create distance from overwhelming internal experiences (Purcell et al., 2024).

Healing and Expanding the Window of Tolerance

There is strong clinical evidence, and growing empirical support, that Dissociative Identity Disorder is treatable (Kluft, 1999; Kluft, 2009; Purcell et al., 2024). Current guidelines emphasize long-term, relational psychotherapy as the primary approach (Chu et al., 2011).

Because DID often develops in the context of early relationships marked by trauma or inconsistency, it can involve a deep loss of trust in others and in oneself (Freyd, 1998; Fung et al., 2025). This may show up as a diminished sense of agency, chronic loneliness, or a profound sense of disconnection from self and others (Adams, 2022).

This creates an important and sometimes painful reality: relationships are often both part of the origin of harm and central to the process of healing.

Therapeutic progress happens within a relationship that is safe, consistent, and collaborative, one that allows for gradual engagement with difficult internal experiences without overwhelming the system (Bromberg, 2003).

The overarching goal of treatment is not to rush the process, but to slowly and safely increase a person’s ability to experience their thoughts, emotions, memories, and bodily sensations as their own. Over time, this expands the window of tolerance and supports greater stability, integration, and overall functioning (Chu et al., 2011).

References

Adams, K. (2022). Attuned treatment of developmental trauma: Non-abused, high-functioning people living outside of time. Routledge.

American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). https://doi.org/10.1176/appi.books.978089042559

Barlow, M. R., & Chu, J. A. (2014). Measuring fragmentation in dissociative identity disorder: The integration measure and relationship to switching and time in therapy. European Journal of Psychotraumatology, 5(1), 22250.

Boyer, S. M., Caplan, J. E., & Edwards, L. K. (2022). Trauma-related dissociation and the dissociative disorders: Neglected symptoms with severe public health consequences. Delaware Journal of Public Health, 8(2), 78–84. https://doi.org/10.32481/djph.2022.05.010

Bromberg, P. M. (2003). Something wicked this way comes: Trauma, dissociation, and conflict: The space where psychoanalysis, cognitive science, and neuroscience overlap. Psychoanalytic Psychology, 20(3), 558.

Chu, J. A., Dell, P. F., Van der Hart, O., Cardeña, E., Barach, P. M., Somer, E., & Twombly, J. (2011). Guidelines for treating dissociative identity disorder in adults, third revision. Journal of Trauma and Dissociation, 12, 115–187.

Elzinga, B. M., Phaf, R. H., Ardon, A. M., & van Dyck, R. (2003). Directed forgetting between, but not within, dissociative personality states. Journal of Abnormal Psychology, 112(2), 237.

Freyd, J. J. (1998). Betrayal trauma: The logic of forgetting childhood abuse. Harvard University Press.

Fung, H. W., Ho, G. W. K., Lam, S. K. K., Chau, A. K. C., Şar, V., Ross, C. A., … Wong, J. Y. H. (2025). The co-occurrence of depression and dissociation: The relevance of childhood trauma. Journal of Psychiatric Research, 183, 157–163.

Kluft, R. P. (1999). An overview of the psychotherapy of dissociative identity disorder. American Journal of Psychotherapy, 53(3), 289–319.

Kluft, R. P. (2009). A clinician’s understanding of dissociation: Fragments of an acquaintance.

Lynn, S. J., Polizzi, C., Merckelbach, H., Chiu, C. D., Maxwell, R., Van Heugten, D., & Lilienfeld, S. O. (2022). Dissociation and dissociative disorders reconsidered: Beyond sociocognitive and trauma models toward a transtheoretical framework. Annual Review of Clinical Psychology, 18(1), 259–289.

Ozturk, E., & Şar, V. (2016). Formation and functions of alter personalities in dissociative identity disorder: A theoretical and clinical elaboration. Journal of Psychology & Clinical Psychiatry, 6.

Purcell, J. B., Brand, B., Browne, H. A., Chefetz, R. A., Shanahan, M., Bair, Z. A., Baranowski, K. A., Davis, V., Mangones, P., Modell, R. L., Palermo, C. A., Robertson, E. C., Robinson, M. A., Ward, L., Winternitz, S., Kaufman, M. L., & Lebois, L. A. M. (2024). Treatment of dissociative identity disorder: Leveraging neurobiology to optimize success. Expert Review of Neurotherapeutics, 24(3), 273–289. https://doi.org/10.1080/14737175.2024.2316153

Savoy, R. L., Frederick, B. B., Keuroghlian, A. S., & Wolk, P. C. (2012). Voluntary switching between identities in dissociative identity disorder: A functional MRI case study. Cognitive Neuroscience, 3(2), 112–119.

Siegel, D. J. (1999). The developing mind. Guilford Press.

Spiegel, D., Lewis-Fernández, R., Lanius, R., Vermetten, E., Simeon, D., & Friedman, M. (2013). Dissociative disorders in DSM-5. Annual Review of Clinical Psychology, 9, 299–326. https://doi.org/10.1146/annurev-clinpsy-050212-185531