I know this is probably super late but I think the previous chole had whats know as anthropophobia (fear of people) because the symptoms that she was depicted with are very similar.
Add in abuse from peers, adults (I think her tutors and possibly even her parents really screwed her over. There is no way that would continue if they cared) in her life. If you think about it, her having a mental illness really sheds light on why she never grew out of some at least some habits.
I so love this battle! It's so thrilling but most of all I cant wait for Nezuko to show up! I wanna see the two siblings kick some demon ass!!! However I also have a feeling that either both wont make it to the end or tanjior will be the one to perish. AHHHH can't wait for the next chapter!!!
This is the third time I've read this manga, and everytime it makes me want to cry. The ending just makes me so relieved and happy for everyone! ╥﹏╥