1.She's really fucked up and truly believes that shit, that means that she's as fucked up as chris, and we know that chris should be in a psychiatric hospital, if anna is as fucked up as chris, she should be institutionalized in a psychiatric hospital as well...
2.(this option seems to be the most likely) She doesn't really believes that, and she just wants to raise her selfsteem by "protecting" chris, that why she has been keeping chris stuck in his shit, because she wants to see him suffer, she wants to see him destroying his life, because she wants feel better with herself, she's not a good friend, or a good person, is just a worthless piece of shit, and a excues for a human being, that's why she keeps feeding chris's paranoia and imaginary problems, if chris managed to somehow develop a better life, she will realize how pathetic and lonely is...
Either way, she's a piece of shit, and she's even worse than chris himself...