Vampire/junkie analogy, anyone?

I'm going out on a limb here, since so far no one else seems to have posted anything on what I thought was the main connection between vampirism and what I interpreted as sheer (pseudo)philosophycal mumble-jumble (but I could be easily wrong given I never really studied philosophy ). I saw the whole vampire thing as merely an over the top analogy for the more mundane drug addiction theme, present throughout the movie, and the philosophycal babble as a take on the human condition and how easily we succumb to carnal desire, in opposition to the blind faith stopping us from doing it, represented by religion, also heavily present in key moments. I'm just too lazy to back up my claim neatly, but I saw the protagonist transformation as an allegory of sorts of her spiraling down to her symbolic death at the end. There's also Williams Burroughs citations, among many others, that don't exactly fit the apparently otherwise philosophy oriented interpretation most people seem to be hung-up onto. I know it doesn't exactly make an airtight case out of what can only be described as mainly sloth (uhhh, bible bad), but I was wondering if anyone else felt the same. Will anyone bother to organize my incoherent gibberish into anything intelligible at all?

We're not evil because of the evil we do, rather, we do evil because we are evil