Persistent Dissociation and its Neural Correlates Uniquely Predict Worse Outcomes after Trauma Exposure

Objective: Dissociation, a disruption or discontinuity in psychological functioning, is often linked with worse psychiatric symptoms; however, the prognostic value of dissociation after trauma is inconsistent. Determining whether trauma-related dissociation is uniquely predictive of later outcomes would enable early identification of at-risk trauma populations. We completed the largest prospective, longitudinal, biomarker study of persistent dissociation to date to determine its predictive capacity for adverse psychiatric outcomes following acute trauma.

Methods: All data were part of the Freeze 2 data release from the AURORA study. Individuals provided self-report data about persistent derealization (N=1,464), a severe type of dissociation, and completed a functional magnetic resonance imaging (fMRI) emotion reactivity task and resting-state scan 2-weeks post-trauma (N=145). We collected 3-month follow-up reports of posttraumatic stress, depression, pain, anxiety symptoms and functional impairment.

Results: Derealization was associated with increased ventromedial prefrontal cortex (vmPFC) activation in the emotion reactivity task and decreased resting-state vmPFC connectivity with cerebellum and orbitofrontal cortex. Furthermore, in separate analyses, brain-based and self-report measures of persistent derealization at 2-weeks predicted worse 3-month posttraumatic stress symptoms, distinct from childhood maltreatment and current posttraumatic stress symptoms.

Conclusions: Our work suggests persistent derealization is both an early psychological and biological marker of worse later psychiatric outcomes. The neural correlates of trauma-related dissociation may serve as potential targets for treatment engagement to prevent PTSD. These results underscore dissociation assessment as crucial following trauma exposure to identify at-risk individuals and highlight an unmet clinical need for tailored early interventions.