where his civilizations, including our own

We've sort of gotten hints that she's got a bit of lasting emotional distress (dementors, for instance) but nothing serious, which I agree you'd expect. She brings it up at Christmas as OotP, and doesn't seem like she's over it, but doesn't sound like it's a huge deal, either. (My problem there is actually that Ginny gives a final word on what it's like to be possessed, when I think that Quirrel, at least, could tell him that there's more than one type of possession.) In terms of a sort of continued posession, perhaps there isn't more to that because diary-Tom was in the past, so when the diary was destroyed, those bits of his soul were also destroyed. That shouldn't eliminate her emotional scarring, though.