Purpose

VA Cooperative Study CSP #591 is designed to compare the effectiveness of two types of psychotherapy, Prolonged Exposure (PE) and Cognitive Processing Therapy (CPT), for treating posttraumatic stress disorder (PTSD) in male and female Veterans. Despite solid evidence that both treatments are effective in Veterans and non-Veterans, there is a lack of evidence about the effectiveness of these treatments compared with one another. The sample will include 900 male and female Veterans with PTSD due to any traumatic military event. Veterans who are eligible and agree to participate in the study will be randomly assigned (by chance) to receive Prolonged Exposure or Cognitive Processing Therapy. The standard "dose" of treatment is 12 weekly sessions but Veterans who improve more rapidly may finish in fewer sessions and Veterans who improve more slowly may have additional sessions. The primary outcome is improvement in PTSD symptoms after treatment. The outcome will be measured at regular follow-up visits that will occur at the middle and at the end of treatment and then 3 and 6 months later. The investigators will measure other outcomes, including additional mental health problems, functioning, quality of life, and use of treatments for mental and physical problems. The investigators also will measure Veterans' treatment preference and examine whether Veterans who get the treatment they prefer do better than Veterans who get the less-preferred treatment. As a large multi-site trial with men and women, CSP #591 is designed to provide conclusive information about whether one treatment is better than the other, overall and for different types of patients-for example, men vs. women, combat Veterans vs. Veterans who experienced military sexual trauma, and older vs. younger Veterans. Regardless of the outcome, patients will have more information to help them make an informed decisions about which treatment to choose and VA will have stronger evidence to help make care Veteran-centered.