Predicting Responses to PTSD Treatment With Iris and Cardiovascular Tests

Post-traumatic stress disorder (PTSD) affects many individuals who experience a traumatic event. There are a variety of treatment options for PTSD, including psychotherapy (talk therapy) options, as well as medications, such as the drug prazosin. Each of the treatment options available is effective at significantly reducing the symptoms of PTSD in some, but not all, individuals with PTSD. However, investigators are not yet able to predict in advance who is likely to respond to which of the available treatments. Neither are the investigators able to explain what changes in the brain after exposure to a traumatic stressors, and why it results in persistent symptoms of PTSD for some people, but not for others. In this study, the investigators are testing two things: First, is testing whether two simple, easy tests of how an individual's blood pressure changes with standing and how an individual's eye reacts to a pulse of light may be able to predict whether that person is likely to respond to the medication prazosin for PTSD. Second, is testing whether those who have been exposed to a traumatic stress show differences in how their body regulates the response to the stress-signal noradrenaline.