I agree. I was so impressed with how this movie built until you felt as itchy and paranoid and claustrophobic as the characters.
Ashley Judd usually plays a strong woman, so I kept expecting her to stand up to her *sshole ex, but she was the realistic abused partner who obediently parroted her abuser, that she earned a punch in the face. Easy to see that she would be influenced by Peter, but when he led her along to the "realization" that she had brought the bugs herself, it was chilling.
The movie also did an amazing job of mixing enough truth with fiction to make it almost plausible that Peter was the subject of military experimentation. Perhaps he was -- just not the way he thought. Who can say? That's part of the brilliance of this movie, that as we see it unfold from Peter and Agnes's point of view, we can wonder if it's possible that Peter was infected with something during his stint in the military. And yet we also see from RC and even the loathsome Goss how psychotic Peter and Agnes have both become.
For those of us who've seen mental illness up close, it is heart-breaking. Overall really thought-provoking film.