It is clear from Eugene Sledge's 2 books, the 2nd was China Marine, that he was sorely afflicted with combat fatigue (PTSD). It was his wife who encouraged him to write the books in an attempt to moderate his condition. I met a man 2 years ago who had done some work for Sledge's son in Hoover, AL. The son said that he remembered as a small boy that his father would retreat to a room to brood.
The man who wrote Flags of Our Fathers said his father never talked about the war--his father was supposedly one of the flag-raisers in the famous photo from Iwo Jima (although some have questioned whether he is actually in the photo).
A former professor at my university (now deceased) was a survivor of the Bataan Death March and spent the rest of the war as a POW. Truly horrendous experiences. He finally wrote a book about his experiences and that seemed to help him.