Ok, as a resident BPD haver, I have input on this (imagine that lmao).
BPD can present itself in varied ways, as long as how it presents still aligns with at least 5 of the 9 diagnostic criteria. Since you only need to match 5 criteria of the 9, it can mix and match in how it presents. With enough treatment/therapy/personal work, BPD symptoms can be minimized and 'go into remission' essentially, though the mental struggle may remain. I could argue all three girls could plausibly have BPD, but for now I'm zeroing in on Rumi.
The BPD diagnostic criteria:
- Frantic Efforts to avoid both real and imagined scenarios of Abandonment
- Unstable and Intense Relationships, alternating between extreme idealization and devaluation (ie splitting).
- Identity Disturbance: Markedly and persistently unstable self-image or sense of self.
- Impulsivity in At Least Two Areas: These areas are potentially maladaptive and self-harming, such as overspending, hypersexuality, substance abuse, reckless driving, and binge eating.
- Recurrent Suicidal Behavior or Self-Harming Behavior: Such as threats or gestures, or self-mutilation.
- Affective Instability due to a marked reactivity of mood. Looks like Mood Swings, often tied to Rejection Sensitive Dysphoria
- Chronic Feelings of Emptiness.
- Inappropriate, Intense Anger or Difficulty Controlling Anger
- Transient, Stress-Related Paranoid Ideation or Severe Dissociative Symptoms (this can manifest as intense dissociation/derealization/depersonalization, paranoid delusions, and in severe cases psychosis)
Now how do these criteria fit Rumi?
Rumi has EXTREME abandonment issues. Like oh dear gods girly is going THROUGH it. That criteria definitely fits.
She's impulsive, as shown by rushing the Golden release, and last-minute changing their Idol Awards song, and various other actions.
Rumi literally kneels at Celine's feet begging her to kill her, I'd definitely call that suicidal behavior.
Rumi has identity disturbance and unstable sense of self in that she has latched so extremely onto her singing voice as the foundation of her identity that anything that negatively affects her voice causes her to spiral in her sense of self. She feels that she is nothing without her voice.
Rumi's outbursts that literally ripple the Honmoon definitely count as difficulty controlling anger in my book. I would wager that most of her anger is focused inward, and so it's more covert, but when her demon side flairs up the outbursts are able to harm the Honmoon.
I would also argue that Rumi's unstable relationship with Jinu - her splitting on him, going from hating him to wanting to save him to being extremely upset with him again to crying when he dies - could mean Jinu was Rumi's Favorite Person/FP for a time.
People with BPD often will latch onto a specific person as their Favorite Person and idealize that person and cling onto them, often to the point of being toxic and hurting their FP. It's possible for someone with BPD to be in a healthy relationship with their FP, but it takes a Lot of work on both sides and healthy communication.
All in all, Rumi definitely meets at least 5 of the criteria, and because she's so repressed, she is in denial about it, and has definitely not gotten any treatment or therapy for it yet. Someone get this girl some DBT therapy ASAP!!!
I could argue Mira also has BPD but is someone who HAS gone to therapy and worked on herself to minimize her symptoms. Mira's most obvious symptoms are the anger issues yes, but I argue she has those managed pretty well comparatively.
Zoey reads as AuDHD but I can definitely also see the BPD presenting in her people pleasing as her method to avoid abandonment. Also in her impulsivity.
Since childhood trauma and invalidating unpredictable upbringings are big factors in the development of BPD, all three girls fit that. Rumi definitely had an invalidating childhood in regards to her demon patterns. Zoey's parents divorcing and Mira's stifling controlling family labeling her a problem child would also fit the invalidating environment bill for causing BPD.
BPD doesn't spring out of nowhere, oftentimes it develops as maladaptive coping skills to deal with an unpredictable invalidating environment. If you get emotionally or physically abandoned as a child, that will stick with you. And then when no longer in that toxic environment, all those maladaptive coping skills only hurt the person with them, and so they have to unlearn them if they want to heal.
BPD and cluster b in general is highly misunderstood and stigmatized and I want more people to know that cluster b's are not inherently abusive monsters, and I'm sure if Rumi got a BPD diagnosis she would absolutely feel even more like a demonic monster because of it. Would definitely add to the shame she feels.
Maybe one day I'll write fic focusing in on my BPD headcanons for them, we shall see.
