Disregarding what it was meant to signify in the text, the description is interesting in any case, because it shows that PTSD is not a contemporary condition, reliant on our specific culture*, to occur, but apparently a more universal phenomenon.

Thank you for pointing this out!

*As I've seen postulated; iirc it had something to do with how our modern western culture distances itself from death and suffering and how we are thus unable to cope when confronted with it, or any other breach of the safety we are accustomed to. Lady Percy's description would be a good argument against that thesis.