CNN —For decades after returning home from World War II, my grandfather did not talk about his wartime experiences. Frank Murphy, the grandfather of CNN's Chloe Melas, after he was captured and taken a prisoner of war by the Nazis in 1943. Everyone could see the physical toll of war on his body, but we didn’t know about his invisible wounds. After World War I, it was “shell shock”; post-World War II it was known as “combat fatigue,” and after Vietnam it was called “post-Vietnam syndrome.” In 1980, the American Psychiatric Association officially recognized it as post-traumatic stress disorder, or PTSD. “When your grandfather and my grandfather served in World War II, they didn’t talk about it,” Paul Rieckhoff, founder and CEO of Iraq and Afghanistan Veterans of America, told me.

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