To be emotionally affected by solitary confinement JA would have to have a soul. She has none. There is nothing there but an intelligent being with no spirit. She never reacts normally. Ever. JMO
I can't speak to whether or not she has a soul. IMO she is a sociopath, whether clinically diagnosed as that of not. But....she has repeatedly demonstrated that she is extremely capable of feeling at least one emotion- hatred.
I think she actively and fiercely hates Travis to this day, and that solitary has only increased that hatred. I also think that even before solitary her hatred for Travis caused her to choose a trial strategy that made little sense other than it provided her with the opportunity to try to destroy Travis' reputation and to cause his family additional pain.
And IMO, her solitary confinement has allowed her to sink deeper into her delusions of victimhood, unchallenged by any reality of what doubling down on that strategy might cost her.