A day later, the nurses begin Susannah's IVIG treatment. IVIG is an abbreviation for intravenous immunoglobulin, a substance made up of healthy antibodies. Susannah explains that normally, antibodies fight intruding pathogens and usually do so quite successfully. Occasionally, however, antibodies can transform into malicious entities and destroy healthy tissue. IVIG neutralizes these bad antibodies.
By describing what's going on at a cellular level in her body, Cahalan creates many different stories about what's happening to her. Further, explaining these treatments spreads awareness and brings them more into the public eye.
Susannah describes a hallucination. She's half asleep, listening to the Ryan Adams video, when a nurse wakes her to take vitals. Susannah feels it's this nurse's fault she's here and is suddenly filled with rage. She punches the nurse in the chest.
Susannah's recovery isn't going to be straightforward, implying that her psychosis is going to come back. Again, her doctors know little about her condition and cannot prepare Susannah's family for surprises like this.
The following morning, Mom finally calls James and lets Susannah speak to him on the phone. Susannah says his name over and over again, and James tries not to cry as he tells Susannah that she'll get better.
Though Mom was trying to protect James by keeping him in the dark, allowing him to speak to Susannah lets him to truly join her support network.
When Dr. Arslan comes by later in the day, he writes that Susannah is beginning to exhibit signs of catatonia. When a person is catatonic, they can be vacant, rigid, mute, and repeat others' words. This same day, Stephen becomes angry with a nurse for asking if Susannah has always been so slow. When he and Dad talk later, they discuss that Susannah is still there, and they must fight for her. In Dad's journal, he writes that he didn't think highly of Stephen when they first met, but he now respects him very much.
The evolving relationship between Dad and Stephen shows that the other characters aren't just changing in relation to Susannah; in the process of caring for her, they're also renegotiating their relationships with each other.