Something that was mentioned about Dawn was that she was more alive in the past. On that note: I've been watching some old videos (3+ years old), and she actually got excited about the food she was about to eat and when asked her opinion, said it was good. This is the first time I've heard her give an evaluation of food instead of just listing the things she tastes.
I couldn't tell you what is different from then to now (ie: medication levels) but I do feel something is different. My guess is that, at least some of the change, is she's tired of this shit and when she's on camera, it's just about getting through it.