That is an interesting take for sure, I interpreted that as more of a spiritual/ethical type comeback than a mental one. Like "how can you reconcile the horrible things you have had to do to survive with your personal sense of morality?" That was kind of the thrust of their conversation, they had both done bad things but Rick was still willing to reach out and help a stranger whereas she couldn't make that leap and had crossed over to pure survival mode.
That is what I took from it too. Could the soul come back from being inhumane, not really the psyche.