It was also considered cowardice so no one was willing to admit to it.
In WW2 in the RAF it was called lack of moral fibre and you were sent straight to the nearest funny farm and got nothing but contempt for being a coward so that really sent you nuts.
I would strongly recommend you read an excellent book with a very crappy title (The Last Torpedo Flyers: The True Story of Arthur Aldridge, Hero of the Skies) BookFinder.com: New & Used Books, Rare Books, Textbooks, Out of Print because it covers the issue and why it came about on multiple occasions - some of the things those poor buggers experienced will blow your mind.
I was given the book many years ago when it was first published and, because of the title, only read it for the first time early last year. It is a warts and all history of one Beaufort torpedo bombing crews experiences in ww2 including how the Beauforts were bombed from above by other RAF aircraft while trying to torpedo their targets during the German channel dash, how one pilot had to land gear up on a jammed on live torpedo as he had injured on board who could not parachute, how one crew managed to get their aircraft home and safe after the pilot went totally bonkers on the wrong side of the channel, how the turret gunners modified their turrets etc.
Although the pilot is named in the title all the remaining crew were involved in writing this book.
You may have seen the documentary "Let There Be Light" which shows interviews with sufferers of PTSD who are being treated after the war. It's remarkable for its straight portrayal of the men, without casting aspersions on their "moral fiber." (Of course this wouldn't be permitted today due to HIPAA rules - the original version even included the mens' names.) It's hard to watch the whole thing, especially if your family was personally touched, but it does offer a measure of hope if you stick with it.