We will first screen participants between the ages of 18 and 60 years for symptoms of PTSD as determined by subjective reporting. We will also screen for healthy control participants to participate in comparison assessment phases of the study. After meeting pre-screen criteria, a more extensive screening to determine the eligibility of each subject will be performed. This will be followed by an EEG. The EEG system measures event-related potentials (ERPs), which explain certain cognitive processes based on changes in the amplitude and timing of electrical changes recorded from the surface of the scalp. We will use an ERP task that includes combat-threatening stimuli as the novel oddball probe to assess P300 response. The amplitude of the P300 (positive amplitude recorded 300 milliseconds after stimulus onset) is used to differentiate between hypo-, normo-, and hyper-arousability. Identifying those with hyperarousal on P300 response on ERP allows for identification of PTSD patients with subjective and objective measures of hyperarousal. The participants will then be scheduled for a neuroimaging session. During neuroimaging, participants will have structural and functional brain scans acquired, including a functional MRI scan using the same threatening/nonthreatening stimuli, thus providing another objective measure of hyperarousal.

Participants will then have active or sham 1 Hz repetitive transcranial magnetic stimulation (rTMS) administered to the right frontal lobe as well as Cognitive Processing Therapy (CPT) once per week for twelve weeks (total 12 rTMS-CPT sessions). Studies have shown that rTMS applied externally to the forehead in the region of the dorsal lateral forehead will safely, reversibly, and painlessly down-modulate the frontal lobe on the side of the head to which it is applied. Our preliminary studies have shown that application of frontal rTMS can reduce the response to threatening stimuli temporarily and this can optimize the effectiveness of the CPT. Following the 12 sessions of rTMS-CPT, the EEG and neuroimaging will be repeated to test for changes in brain function.

In summary, the study involves approximately 19 visits. Treatment is once a week for 12 weeks followed by a 1 month, 3 month and 6 month follow-up appointments.