AITAH for not asking my best friend about her mental health issues?

I (27f) had a best friend, we'll call her Raven (30f) for almost 6 years. I met her at a work place, we bonded over shared interests, roomed together for a couple years, and had a really great friendship in my opinion. About a year ago, she went on some internet rabbit hole about multiple personality disorder. She decided after ONE DAY of researching it that she had it. Everything past that point spiraled downward in our friendship because EVERYTHING revolved around her new personalities.

This felt like a cry for attention to me and I'll be honest, I never took it seriously but I did not outwardly belittle it or anything. She has a tendency to get carried away with ideas and obsess over it and completely lose her grip on reality so I did NOT want to support the idea she had this mental illness without her going to an actual professional because I do not trust her mind in full honesty. I expressed my concern that this idea could spiral into other issues and suggested she see a therapist or something about it if she genuinely felt she had it.

She named them, she made different profiles for them, constantly telling me their origin stories, etc. I foreal tried to be supportive. But then she started "losing her memory" and started switching in the middle of EVERY SINGLE conversation. Claiming she didn't even remember our shared interests or KNOW ME in certain personalities. Like this never happened in our entire friendship and you're telling me now, 5+ years into our friendship, you all of a sudden can't stay in one personality for a conversation? It felt like everything revolved around her different personalities.

So then she said to me I was ABUSIVE for not asking her about each of them. And I was like girl I can't ask questions I don't have.. you've explained these personalities at length. She stopped being my friend because she "realized things about me and our friendship" and just ghosted me and started posting all on facebook about how abusive and dismissive I am. It's so fucking childish. We are fully grown adults and idk where this behavior came from. Am I really that much of an asshole for not taking this totally seriously? I honestly felt it would be sort of enabling some sort of psychosis if I supported this idea too much so if I'm honesty, yeah, I never took it very seriously. It was honestly just annoying to me because she kept escalating it and literally ALL of our conversations surrounded her switching into other personalities and not even remembering what we were talking about. It got really fucking old really quick and I didn't even feel she was the same person I grew close with.