Resting‐state functional connectivity in patients with a complex PTSD or complex dissociative disorder before and after inpatient trauma treatment

INTRODUCTION: Recent research suggests that traumatized patients are characterized by disrupted resting‐state functional connectivity. We examined whether neural networks involved in resting‐state change over the course of a phase‐oriented inpatient treatment for complex traumatized and dissociative disorder patients. We also investigated associations between these network alterations and clinical symptoms and emotion regulation skills. METHODS: Pre‐ and post‐treatment, electroencephalography (EEG) was recorded during resting‐state in patients (n = 23) with a complex dissociative disorder (CDD) or complex posttraumatic stress disorder (cPTSD). Patients also completed clinical and emotion regulation questionnaires. To reduce variance in the collected data, patients were exclusively tested as one prototypical dissociative part referred to as Apparently Normal Part (ANP). Functional network connectivity was examined and compared with a matched healthy control group (n = 37), also measured twice. RESULTS: Prior to treatment and compared with controls, patients had a significantly lower functional connectivity strength within eyes‐open and eyes‐closed resting‐state networks in the theta and alpha frequency band. Following treatment, functional connectivity strength within these networks was comparable to the control group and comprised areas belonging to the default mode network (DMN) and prefrontal as well as anterior cingulate control regions. Treatment‐related network normalizations in the theta frequency band were associated with a self‐reported increase in the use of cognitive reappraisal strategies and reduction in emotion regulation difficulties. CONCLUSION: Phase‐oriented trauma treatment can strengthen resting‐state network connectivity and can increase the capacity of complex traumatized and dissociative patients as ANP to handle emotional challenges effectively.