There are reasons for why someone with BPD would act as if he or she has multiple personalities. To some extent, it makes sense that people would somewhat adjust their behavior according to different situations. A normal man is expected to be solemn at church, and more jocular at a party. You wouldn't expect him to be loud and raucous at a church. . . . Well, actually, I would be, but I'm not normal. And thank goodness for that! Hee-hee! ^_^ Anyhow, that sort of adjustment is normal to some degree. However, in many cases of someone with BPD, the personality changes are often much more extreme -- to the point where they greatly interfere with domestic life.
In public, someone with undiagnosed, partially-treated, currently-untreated BPD symptoms may appear to be a tough, unemotional, invincible businessman or -woman. But when the guard comes down, he or she might start sniffling over something that you wouldn't ordinarily expect someone to cry about -- such as about someone tastefully complimenting him or her -- and talk to you in the voice of a lost, little child. And this change can sometimes be very sudden and happen at the slightest provocation. If you're unfamiliar with BPD symptoms, this can seem very surprising. You may feel tempted to ask the multiple-persona person, "Which of your personalities is 'the real you'?" The truth, whether that person recognizes it or not -- is that all the different personality facets are the "real" one; it's just that they haven't been as smoothly integrated as you would expect with most people.
This is related to the identity disturbances, wherein someone can take on a certain persona for several months and then "change" again, or might even change self-identified sexual orientation every few months or years (see here for an example of changes in sexual orientation). Though someone with undiagnosed, currently-untreated BPD might stress his or her repeated personality "c-h-a-n-g-e"s throughout life, there is a factor that will sadly remain constant if psychiatric care remains absent: the presence of these life-thwarting symptoms. Insofar as someone with severe, untreated, undiagnosed BPD refuses any return to psychiatric care, a very beneficent, happy, authentic change is exactly what is missing. (For a good description of the identity issues, see this essay.)
This seems to be related to the issue of "splitting." If someone is "splitting," it means he or she has very unbalanced, whim-based, polarized, and completely nuance-free shifts in her evaluations of other people. With greater emotional attachment to a person comes more intense shifts in these evaluations. Consider a boy ranging in age from newborn to about seven years old. When a mother is nurturing her newborn baby boy, who is confined to his cradle, he sees her as all-benevolent. But when she walks away from his cradle, it's not as if he can go after her. He cannot be sure that she will ever return to his side -- as far as he can understand it, she is abandoning him, perhaps forever. In these periods, the mother is not seen as all-benevolent but infinitely neglectful, infinitely cold-hearted, and ultimately undependable.
Likewise, consider this same boy when he is four years old. Again, when his mother is lavishing attention on his adorableness, he sees her as all-good, all-nurturing, all-loving. But when she scolds him or disciplines him, he feels humiliated. At this particular juncture, she switches to all-malevolent, all-hateful. There is no nuance in this; for many children this age, it's hard to comprehend the idea that you can approve of some aspects of your mother's personality and disapprove of other parts of her while loving her overall.
For many people with undiagnosed, currently-untreated BPD, there is a similar phenomenon at work. This person can become fixated on you and lavish you with adulation, as if you are the all-nurturing mother this person has always wished for. You can be the most masculine man in the world, and you can still be regarded, on some level, as that much-yearned-for mother figure (I repeat: you, as a man, can be seen as a strong mother figure, not father figure). But when you disappoint this person, that vision is shattered. No matter how much this person proclaimed your supreme value, you can then instantly be cast into the dog house. In his or her eyes, you become something that deserves zero attention or respect. To this person, you become something beyond contempt, a speck of dust.
When you have first been idolized by such a person, and then, soon afterward, given the cold-shoulder by this same person over nothing, it can make you wonder if the prior idolization was genuine. It makes the person look shallow at best, insincere at worst. But in such cases, what often happens is that, in those moments of adulation, that person meant it. Likewise, when that person was treating you like garbage, that was what was meant, too.
It's not that the person is consciously being dishonest in either case; it's that the person is acting according to strong whims with the same psychological complexity as a four-year-old boy would react to you. It's very easy for a four-year-old boy to instantly shift from seeing you as all-great to all-crummy. The same principle can apply to the emotional reactions you receive from someone with undiagnosed, currently-untreated BPD. You can find a helpful description of this "splitting" over here. And now I will quote another accurate description of "splitting":
Devaluation is when they suddenly behave as if they don't value you anymore. They become inexplicably cool toward you for no discernible rhyme or reason. And they seem to have no memory of how much they adored you yesterday.
They may be doing this as a reaction to feeling abandoned. And they may feel abandoned at the *slightest* sign of rejection from someone. It may be something as inconsequential as you showing up 10 minutes late for a date. Or they might imagine you were paying attention to someone else in a sexual way, etc. Many things can trigger their fear of abandonment.
They also typically devalue their partners at times when a relationship is becoming especially close or is about to move to a new level... this also triggers their fear of abandonment. Things have become too close, they become frightened, and they push the partner away. Often, this response is an automatic reaction, more of a reflex, and not something to which they give much conscious thought. And they truly can forget how much they cared about you yesterday... they live very much in the moment... and their mood of the moment is all encompassing, they can forget everything else.
Devaluation is usually a part of a cycle of Idealization and Devaluation. They go back and forth between these two extremes of feeling for their partner. This is the push/pull dynamic of BPD. They devalue and push the partner away until there is too much distance...
Perhaps you know someone who has symptoms of undiagnosed, currently-untreated BPD. Perhaps this person repeatedly proclaimed undying love for you. Then this person went through a scary phase and, a week later, started treating you like dirt. Was this person's prior declarations of love all a lie? I think you will find that, when proclaiming love, this person believed it at the time. Likewise, when this person was treating you like dirt, this person assumed it emotionally justified, at the time. This is how someone with treated, diagnosed BPD describes it [when you go to the link, it's in the margin on the right]:
Some partners of people with BPD worry the relationship was just a game, that their SO [significant other] was using them and felt nothing for them. That's not true.
I am a recovering BP [Borderline Personality].
Before, when I was in a relationship, my feelings felt genuine. I didn't have a conscious ulterior motive. There was an authentic connection; and while it may have been unhealthy and for the wrong reasons, it was, in my mind, real.
I acted as if I was in love because I thought I was.
The bond that occurred in the beginning of a relationship was incredible: there was a deep (false) sense of knowing the other person intimately, intuitively. He became my whole world and it was wonderful, rapturous. When my boyfriends left – and they invariably left – that world was anhiliated; everything fell to ashes. . . . The saddest thing about the situation was that I was the cause of my pain, yet had little idea then that it was due to my own behavior.
So yes, the love is “real”, but only in the sense of how it feels to the person with BPD: the feelings seem real, they feel like love.
This is a video that describes a more severe (to me) version of the "fragmented personalities" phenomenon.
Below is a video from the mental health vlogger and recovering BPD sufferer Dani Z. She is much more chipper and more self-aware than those whom I have known who have shown symptoms of what looks like untreated, undiagnosed BPD. But Dani Z being more chipper and self-aware is part of the fact that there is individual variation among different cases of people who have BPD.
