rTMS-augmented Written Exposure Therapy for PTSD

Inclusion Criteria: -All veterans are eligible to be included in the study if they meet all the following criteria: * veteran; * English-speaking and able to provide written informed consent; * diagnosed with PTSD; * between the ages of 18 and 60 years. Participants over age 60 will not be included, as aging is known to impact brain structure, and thus the potential accuracy of the rTMS target, independently of PTSD. Exclusion Criteria: * Individuals with history of seizures or other serious neurological history including acquired, developmental or degenerative neurologic illness, identified through medical chart review, will be excluded due to potential lowered threshold for seizures during rTMS stimulation. * The effects of rTMS are unknown on fetal development, therefore, women who are pregnant will be excluded. * Participants will also be screened and excluded if any of the following are met: * current psychosis including psychotic disorder, * bipolar disorder, * schizophrenia; or another severe cognitive or psychiatric disorder; * positive screen for current suicidal intent and plan \[with a score of 2 or 3 on BDI-2 item 9\]; * current substance use disorder; or substance use in the last 12 hours before the rTMS session. * The investigators note that PTSD is often comorbid with traumatic brain injury (TBI) in military veterans who were deployed to a war zone. The investigators will use the Department of Defense and Veterans Affairs consensus-based classification of TBI severity for classification of TBI. * Participants with moderate or severe TBI will be excluded. * Participants with mild traumatic brain injury (mTBI) or concussion will be enrolled. This will enhance the ecological validity of the study. * Participants with cognitive impairment as evidenced by a Montreal Cognitive Screen (MoCA) less than 23/30 or estimated baseline intellectual ability of a standard score of less than 80 on a word reading test will be excluded due to potential neurocognitive differences. * Participants on psychotropic medications will not be excluded, but participants will be required to be stable on their medication for at least four weeks prior to beginning the study and throughout the time of study. * Participants enrolled in long term, supportive psychotherapy (i.e. not an evidence-based psychotherapy (EBP)) may continue to be involved in their treatment throughout the study. However, participants involved in a concurrent EBPs will be excluded. Participants will be asked to disclose whether they chose to participate in an EBP during the course of the treatment or followup phases of the study.