So Ootani Masae's gone on hiatus. She says it's due to depression and panic disorder.
http://ameblo.jp/masae-otani/entry-12290651801.html
At the time of the blog post she said she's been undergoing treatment for a month and already feels like it's helping her.
She gets panic attacks being in crowded areas (especially places like movie theatres) and it was getting to the point where she stopped going outside at all. She's not entirely sure what the cause of it all is, and she realised that just being on medication wasn't helping her get better.
She also asks people not to feel sorry for her because she's depressed.
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Hope she manages to get at least somewhat better. It sounds like she was (is?) in a pretty dark place but at least she's seeking help. That's the most important part.