Abstract
Objective:
Posttraumatic stress disorder (PTSD) is a highly prevalent psychiatric disorder associated with disruption in social and occupational function. Transcranial magnetic stimulation (TMS) represents a novel approach to PTSD, and intermittent theta-burst stimulation (iTBS) is a new, more rapid administration protocol with data supporting efficacy in depression. The authors conducted a sham-controlled study of iTBS for PTSD.
Methods:
Fifty veterans with PTSD received 10 days of sham-controlled iTBS (1,800 pulses/day), followed by 10 unblinded sessions. Primary outcome measures included acceptability (retention rates), changes in PTSD symptoms (clinician- and self-rated), quality of life, social and occupational function, and depression, obtained at the end of 2 weeks; analysis of variance was used to compare active with sham stimulation. Secondary outcomes were evaluated 1 month after treatment, using mixed-model analyses. Resting-state functional MRI was acquired at pretreatment baseline on an eligible subset of participants (N=26) to identify response predictors.
Results:
Retention was high, side effects were consistent with standard TMS, and blinding was successful. At 2 weeks, active iTBS was significantly associated with improved social and occupational function (Cohen’s d=0.39); depression was improved with iTBS compared with the sham treatment (d=−0.45), but the difference fell short of significance, and moderate nonsignificant effect sizes were observed on self-reported PTSD symptoms (d=−0.34). One-month outcomes, which incorporated data from the unblinded phase of the study, indicated superiority of active iTBS on clinician- and self-rated PTSD symptoms (d=−0.74 and −0.63, respectively), depression (d=−0.47), and social and occupational function (d=0.93) (all significant). Neuroimaging indicated that clinical improvement was significantly predicted by stronger (greater positive) connectivity within the default mode network and by anticorrelated (greater negative) cross-network connectivity.
Conclusions:
iTBS appears to be a promising new treatment for PTSD. Most clinical improvements from stimulation occurred early, which suggests a need for further investigation of optimal iTBS time course and duration. Consistent with previous neuroimaging studies of TMS, default mode network connectivity played an important role in response prediction.
