What an interesting topic!
On the history of PTSD, I think "shell shock" was more in reference to WWI folks (my grandfather, sadly). In the 50s, they were using terms like "gross stress reaction" and where I would look would be on the history of how we understand the concept of "stress". You probably have this link
http://www.brainline.org/content/20...isorder-a-history-and-a-critique_pageall.html which is pretty basic but does mention WHO was working in this area (before we had the DSM) . The article linked above mentions Alexandra Adler who was highly instrumental in linking the concept of traumatic reaction to civilian experiences (fire) and deepening our understanding of how PTSD works.
As far as repressed memory goes, definitely you could find great stuff from Hebb -(and people who are familiar with memory research would certainly know his work), but the guy you have to look at is Bessel van der Kolk. He is really the leading guy in PTSD work, and has a lot to say about traumatic memory, how it differs from other sorts of memory, problems with encoding and retrieval and so forth. His work is very current though (but gives an excellent description of how we understand the legacy of trauma
today)
Yes, repressed memory is highy controversial in our field but you are looking at how it was perceived in the 1950s, right? I think I would look up interference theory and memory, which I
think was pretty dominant at the time. Of course, Freud's disciples would see it as a defense mechanism (Freud wrote about it).
No, this is not an area I would consider making things up as many,many people are very familiar with the history of memory research, trauma and cognitive psychology, and also...it's really cool stuff!!!
Good luck!