Neural Mechanisms of Mindfulness-based Cognitive Therapy (MBCT) for Posttraumatic Stress Disorder (PTSD)_VA Only

This study will examine the effects of psychotherapy as treatment for PTSD. This research will see how brain activity and brain connectivity is affected by Mindfulness Based Cognitive Therapy (MBCT) and Muscle Relaxation Therapy (MRT). Participants that qualify to be in this study will receive 8 weeks of group therapy in MBCT or MRT. Prior to receiving therapy participants will: complete baseline assessments related to their PTSD; fill out surveys; have an functional magnetic resonance imaging (fMRI); and provide a saliva sample. These assessments will be repeated after the therapy is over. Overall study participation should last approximately 10-12 weeks.