A Review of the Neurobiological Basis of Trauma-Related Dissociation and Its Relation to Cannabinoid- and Opioid-Mediated Stress Response: a Transdiagnostic, Translational Approach

Dissociative experiences have been associated with increased disease severity, chronicity, and, in some cases, reduced treatment response across trauma-related and other psychiatric disorders. A better understanding of the neurobiological mechanisms through which dissociative experiences occur may assist in identifying novel pharmacological and non-pharmacological treatment approaches. Here, we review emerging work on the dissociative subtype of posttraumatic stress disorder (PTSD), and other trauma-related disorders providing evidence for two related overarching neurobiological models of dissociation, the defense cascade model of dissociation and Mobb's threat detection model. In particular, we review neuroimaging studies highlighting alterations in functional connectivity of key brain regions associated with these models, including connectivity between the prefrontal cortex, the amygdala and its complexes, the insula, and the periaqueductal gray. Work implicating the kappa-opioid and endocannabinoid systems in trauma-related dissociative experiences is also reviewed. Finally, we hypothesize mechanisms by which pharmacological modulation of these neurochemical systems may serve as promising transdiagnostic treatment modalities for individuals experiencing clinically significant levels of dissociation. Specifically, whereas kappa-opioid receptor antagonists may serve as a pharmacological vehicle for the selective targeting of dissociative symptoms and associated emotion overmodulation in the dissociative subtype of posttraumatic stress disorder and transdiagnostically, modulation of the endocannabinoid system may reduce symptoms associated with emotional undermodulation of the fight or flight components of the defense cascade model.