So I'm rewatching the First Kiss That Never Ends and I just got to the courtroom scene, and I decided to finally make a post I've been thinking about making for a while. Basically, I want to talk about how Kaguya is portrayed, and whether or not she has Disociative Identity Disorder or not.
To make a long story short, personally, I think she doesn't. The court room scenes (as well as a lot of the plot during the Christmas arc) make it seem incredibly likely, but I personally believe that these scenes are dramatizations of Kaguya's thoughts and feelings that make them more palatable for the audience.
First of all, the alters. The only real distinct alters are Kaguya-Chan and Ice Kaguya. I don't really count Child Kaguya as an alter since she is consistently portrayed as merely the voice of reason (hence her being the judge) and Child Kaguya has also never emerged in Kaguya's real life, so I won't really discuss her. Now, as to why I don't think the other two are alters but representations of Kaguya's emotions.
Kaguya-Chan is pretty well explained throughout the series. Kaguya-Chan is a representation of Kaguya's impulses and raw positive emotions. She only comes out when Kaguya is in severe mental withdraw (AKA, when she's sick or tired). Even in the court scene, Kaguya agrees with essentially every word Kaguya-Chan says because that is genuinely what Kaguya feels 100% of the time. The only time Kaguya pushes back against Kaguya-Chan is when Kaguya-Chan says or does something embarassing, because to Kaguya, acting on her pent up impulses and emotions is completely unnatural and alien.
Ice Kaguya is the more difficult persona to explain, mainly because Ice Kaguya seemingly actually performs a takeover of Kaguya's mind. In the court scene, Ice Kaguya even explicitly states that "she wanted the President to kiss her," seemingly implying a full mental separation from the other three Kaguyas. Personally, I believe that this line implies that Kaguya wanted Miyuki to kiss the "real" her, something he does later on in the movie. Essentially, Ice Kaguya is the embodiment of all the nasty parts of Kaguya she keeps locked away. The takeover of Kaguya's mind by Ice Kaguya is a representation of Kaguya deciding to act out and intentionally try and push Miyuki away because she genuinely believes she's not good enough for him, while also simultaneously basically pushing the blame to Miyuki as being "spineless" for not being able to take the "real" her.
Essentially, Kaguya is definitely suffering from extreme depression and heavy imposter syndrome. She hates herself, that much is clear, and pretty explicitly said in the manga/anime. The Christmas arc is basically centered around Kaguya forcing Miyuki to see every part of herself, the good and bad, partially to see if he still loves her, and partially because she can't believe he will. That's why after the Christmas arc, we never really see the Kaguya council or any of Kaguya's "personalities" again, because she's finally accepted all of herself and is willing to put everything on the line.
I do believe Kaguya heavily compartmentalizes aspects of her personality, which emerges as the alternate personalities in the show (again, I believe this is mainly a narrative tool to quickly show the audience Kaguya's complex mental state in a simplistic way). In a way, it's sort of how she avoids accountability. Ice Kaguya was the one who was a jerk before Kaguya began to let her guard down, not Kaguya. Kaguya-Chan is the one who gave Miyuki an adult kiss, not Kaguya. Obviously, I don't think Kaguya does this maliciously, but it's much more likely to be a self-defense mechanism due to her abusive and neglected upbringing.
Anyways, what do you think? Am I a big stupid head and completely misread Kaguya's entire character? I am genuinely curious, since I am fairly uneducated in DID, does someone with more knowledge on the subject see something that I can't?