Brain State Dynamics in Ketamine-Induced Dissociation Resemble Those in Posttraumatic Stress Disorder

Dissociation, an altered state of consciousness in which individuals feel detached from their body, environment, and sense of self, is a common feature of posttraumatic stress disorder (PTSD). Despite its significance, the neurocognitive processes underlying dissociation remain poorly understood, potentially limiting diagnostic precision and treatment efficacy in PTSD.

To address this gap, we applied network control theory to resting-state functional magnetic resonance imaging to examine neural dynamics during dissociative states in 2 contexts: healthy volunteers (n = 30) undergoing intravenous administration of ketamine, an anesthetic known to induce dissociative states, and patients with PTSD receiving an intervention aimed at alleviating dissociative symptoms (a secondary analysis of data from 78 patients who participated in previously conducted clinical trials).

Ketamine administration led to resting-state brain dynamics resembling those observed in patients with PTSD before treatment, characterized by an increased dominance of a default mode network (DMN) meta-state and a decreased dominance of a somatomotor network (SOM) meta-state. Posttreatment reduction in the dominance of the DMN meta-state correlated with a decrease in dissociative symptoms in patients with PTSD. Computational modeling analysis revealed that after treatment, patients with PTSD exhibited a more organized and less entropic brain state. However, contrary to our hypothesis, ketamine administration did not lead to significant changes in these entropy-related indices.

Dissociative states, whether induced by pharmacological manipulation or clinical condition, are accompanied by increased dominance of the DMN meta-state and reduced dominance of the SOM meta-state.