They didn't release her just because she had a nervous breakdown. Apparently there were medical issues as well.
However, the nervous breakdown bit doesn't surprise me, but it's not why she was released. Seriously though... who in their right mind ever imagined her fulfilling the entire sentence anyways.
p.s. the fact that I'm even writing about this girl right now irritates me. I hate how society has absolutely no choice but to be involved in the lives of worthless people with lots of money and fame.