A veteran of the Iraq War with post-traumatic stress disorder talks to physical therapist Nicole Bormann before a session in the VA Medical Center in St. Louis. Chris Hondros/Getty Images hide caption

itoggle caption Chris Hondros/Getty Images

Brothers Deven (left) and Erik Schei ride by President Barack Obama on the South Lawn of the White House as part of the sixth annual Wounded Warrior Project's Soldier Ride on Friday. Saul Loeb/AFP/Getty Images hide caption

itoggle caption Saul Loeb/AFP/Getty Images

Members of the 182nd Infantry Regiment arrive in Indiana after spending a year in Afghanistan. They will spend about a week here before returning to their homes in New England. Tom Dreisbach/NPR hide caption

itoggle caption Tom Dreisbach/NPR

Gen. Peter Chiarelli, former vice chief of staff for the U.S. Army, says the Army lacks reliable diagnostic tools to screen for mental health. Susan Walsh/AP hide caption

itoggle caption Susan Walsh/AP

U.S. Brig. Gen. Kevin Bergner speaks in Baghdad in July 2007 near a poster of Ali Musa Daqduq. Daqduq was captured in Iraq in March 2007, and is accused of orchestrating the killings of five U.S. soldiers. The U.S. left Daqduq in Iraqi custody when U.S. troops formally withdrew in December. But the Obama administration is seeking to try him before a military commission. Wsthiq Khuzaie/AP hide caption

itoggle caption Wsthiq Khuzaie/AP

Hell and Back Again focuses on Sgt. Nathan Harris' life on the battlefield in Afghanistan and at home in North Carolina. Courtesy Danfung Dennis hide caption

itoggle caption Courtesy Danfung Dennis

Traumatic brain injuries are most often caused by powerful blasts from improvised explosive devices. A roadside bomb explodes, and the concussive effect violently shakes the brain inside the skull. Stefano Rellandini/Reuters /Landov hide caption

itoggle caption Stefano Rellandini/Reuters /Landov