Shellshock. Battle fatigue. Post-traumatic stress disorder. These invisible wounds of war have been with us as long as combat itself. Listen to the story of Joe Merritt, a former Marine and Army National Guard soldier, and meet his wife, Sonya. Learn about an effective evidence-based treatment for PTSD: virtual reality exposure therapy. We'll talk with Terri Tanielian, a senior behavioral scientist at RAND; Skip Rizzo, psychologist and director for medical virtual reality at USC Institute for Creative Technologies; and Barbara Rothbaum, clinical psychologist and executive director of the Emory Healthcare Veterans Program. For more information on Veterans in America, visit rand.org/veteranspodcast.