Integrating Dissociation

Constructing a mental self-continuity of consciousness, memory, and identity is a task, not a given. Our mental life is full of discontinuities: sleep and wakefulness, sad and happy moods, loneliness and social connection, safety and trauma. Sudden positive as well as traumatic events are often accompanied by a sense of disbelief, as though they were happening to someone else. Our brain processes experiences bottom-up, not top-down, through associative networks that facilitate storage and retrieval. Neurons that fire together wire together through long-term potentiation that strengthens synapses. Events and relationships in our lives shape how we perceive and understand ourselves. The coherence of identity that is constructed as life unfolds is never seamless.

For some, the cracks in identity are marked, as in dissociative identity disorder, in which elements of personal identity are experienced as distinct—different ages, stores of memory, predominant moods, and social skills. For others, the poorly integrated components involve primarily memory, as in dissociative amnesia, or perception, as in depersonalization/derealization disorder. But dissociative disorders have themselves been dissociated from psychiatric nosology, viewed as odd and somehow less “real” than bread-and-butter psychiatric disorders such as schizophrenia, depression, and borderline personality disorder. For this reason in particular, Lyssenko and colleagues, in an article presented in this issue (1), have performed a particular service to psychiatry in general and dissociation in particular by reporting a thorough meta-analysis of studies examining dissociative experiences using the Dissociative Experiences Scale (DES) among a wide variety of psychiatric populations. Their thorough search of electronic databases led them to 216 articles involving 15,219 people. They employed sophisticated meta-analytic techniques to compare findings across these studies. Not surprisingly, they found the highest DES scores among those diagnosed with dissociative identity disorder, which certainly provides evidence of construct validity for the undertaking. Posttraumatic stress disorder (PTSD) was identified as having the next highest range of DES scores. This is not surprising, both because of the frequency with which a history of significant trauma is associated with dissociative disorders (2) and because of—as the authors note—the inclusion of a dissociative subtype of PTSD in DSM-5 (3). The inclusion of the dissociative subtype in DSM-5 was based on evidence that a substantial minority (about 14%) of a large sample (25,018) of individuals with PTSD also suffer significant depersonalization and/or derealization and are characterized by a history of more severe and earlier trauma, suicidal ideation, and more functional impairment (3). Functional neuroimaging showed that trauma survivors with more dissociative symptoms had a pattern of hyperfrontality and limbic inhibition that was the opposite of that seen among those with the more common hyperarousal type of PTSD, who had limbic hyperactivation and hypofrontality (4). Other studies employed latent class analysis and related techniques to look at the clustering of symptoms among trauma survivors and identified a distinct subgroup with dissociation (5, 6). Thus, a substantial subgroup of those with PTSD have significant dissociative symptoms, and indeed, they respond less well to standard exposure-based psychotherapy and better to treatments that assist them with self-stabilization as well (7, 8). So identifying and understanding dissociative symptoms in PTSD beyond the standard flashbacks, numbing, and amnesia improves treatment outcome as well as our understanding of the disorder.

The nosological group with the third highest scores on the DES was those with borderline personality disorder. There is growing evidence of trauma history as an etiological factor in this disorder (9–12). There is even evidence that psychotherapy for borderline personality disorder alters frontolimbic circuits (13).

Lower but still substantial ranges of DES scores were found among those with schizophrenia, somatic symptom disorders, eating disorders, and anxiety disorders, and scores were lower still among those with depression and bipolar disorder. However, all of the clinical samples had higher dissociation scores than those found in healthy samples. In some cases, as the authors conjecture, higher dissociation scores may be due to comorbidity with other psychiatric disorders that are more typified by dissociation. But the findings also suggest that dissociation more often than not has psychopathological implications.

This study suggests that, just as we identify and treat uncontrolled extremes of mood and defects in cognition, we can help many of our patients more if we identify problems with integration of identity, memory, perception, and consciousness. It is time to better integrate dissociation into our overall understanding of mental dysfunction.