A single dose of a dissociative drug altered resting-state functional connectivity between frontal and limbic brain regions in individuals with posttraumatic stress disorder, suggesting a potential mechanism for its therapeutic effects. The randomized controlled pilot study compared drug versus placebo in a small sample, finding changes in connectivity patterns that may relate to symptom reduction. The authors indicate that these preliminary results warrant further investigation in larger trials.
A subanesthetic dose of ketamine did not increase resting-state functional connectivity between the medial prefrontal cortex and amygdala in individuals with PTSD, contrary to prior correlational findings. Instead, ketamine produced a stronger transient decrease in vmPFC-amygdala connectivity compared to the control drug midazolam. These preliminary results from a randomized controlled pilot study challenge the view that dissociation involves emotion overmodulation via increased fronto-limbic connectivity, suggesting a more nuanced neurobiological understanding of dissociative phenomena in PTSD is needed.