Results from a neuroimaging study showed that different dissociative symptoms were linked to hyperconnectivity within several key regions of the brain, including the central executive, default, and salience networks as well as decreased connectivity of the central executive and salience networks with other brain areas.
Depersonalization/derealization showed a different brain signature than partially dissociated intrusions, and participants with posttraumatic stress disorder showed a different brain signature, compared with those who had dissociative identity disorder (DID).
“Dissociation is a complex, subjective set of symptoms that are largely experienced internally and, contrary to media portrayal, are not usually overtly observable,” lead author Lauren Lebois, PhD, director of the Dissociative Disorders and Trauma Research Program, McLean Hospital, Belmont, Mass., and assistant professor of psychiatry at Harvard Medical School, Boston, told this news organization.
“However, we have shown that you can objectively measure dissociation and link it to robust brain signatures. We hope these results will encourage clinicians to screen for dissociation and approach reports of these experiences seriously, empathetically, and with awareness that they can be treated effectively,” Dr. Lebois said.
The findings were published online in Neuropsychopharmacology.
Detachment, discontinuity
Pathological dissociation is “the experience of detachment from or discontinuity in one’s internal experience, sense of self, or surroundings” and is common in the aftermath of trauma, the investigators write.
Previous research into trauma-related pathological dissociation suggests it encompasses a range of experiences or “subtypes,” some of which frequently occur in PTSD and DID.
“Depersonalization and derealization involve feelings of detachment or disconnection from one’s sense of self, body, and environment,” the current researchers write. “Individuals report feeling like their body or surroundings are unreal or like they are in a movie.”
Dissociation also includes “experiences of self-alteration common in DID, in which people lose a sense of agency and ownership over their thoughts, emotions, actions, and body [and] experience some thoughts, emotions, etc. as partially dissociated intrusions,” Dr. Lebois said.
She added that dissociative symptoms are “common and disabling.” And dissociation and severe dissociative disorders such as DID “remain at best underappreciated and, at worst, frequently go undiagnosed or misdiagnosed,” with a high cost of stigmatization and misunderstanding preventing individuals from accessing effective treatment.
In addition, “given that DID disproportionately affects women, gender disparity is an important issue in this context,” Dr. Lebois noted.
Her team was motivated to conduct the study “to learn more about how different types of dissociation manifest in brain activity and to help combat the stigma around dissociation and DID.”
Filling the gap
The investigators drew on the “Triple Network” model of psychopathology, which “offers an integrative framework based in systems neuroscience for understanding cognitive and affective dysfunction across psychiatric conditions,” they write.
This model “implicates altered intrinsic organization and interactions between three large-scale brain networks across disorders,” they add.
The brain networks included in the study were the right-lateralized central executive network (rCEN), with the lateral frontoparietal brain region; the medial temporal subnetwork of the default network (tDN), with the medial frontoparietal brain region; and the cingulo-opercular subnetwork (cSN), with the midcingulo-insular brain region.
Previous neuroimaging research into dissociative disorders has implicated altered connectivity in these regions. However, although previous studies covered dissociation subtypes, they did not directly compare these subtypes. This study was designed to fill that gap, the investigators note.
They assessed 91 women with and without a history of childhood trauma, current PTSD, and with varying degrees of dissociation.
This included 19 with conventional PTSD (mean age, 33.4 years), 18 with PTSD dissociative subtype (mean age, 29.5 years), 26 with DID (mean age, 37.4 years), and 28 who acted as the healthy control group (mean age, 32 years).
Participants completed several scales regarding symptoms of PTSD, dissociation, and childhood trauma. They also underwent functional magnetic resonance imaging. Covariates included age, childhood maltreatment, and PTSD severity.