Why is it that a BPD does what she does? What is the root cause of it all? Easy. The only that matters to them. Fear of being abandoned.
To strangers, someone with BPD may not seems like anyone out of ordinary. And they completely believe her when she says “I’m fine”. Which is actually good. Because she knows they are strangers, she knows they are already on the outside and thus unable to come into her world to hurt her, to leave her wounded. She knows they haven’t done anything wrong because there is nothing for them to do. And so, her interaction with the world ‘outside’ is completely normal, devoid of any storm that is ravaging her souls inside.
What storm you ask? Well, if you know then you don’t need to ask, if you ask then you don’t need to know. The problem is when she start having people inside her world. Either because they were stranded there or they were pulled in, as in having a crush or making new friends. The closer they are to her, the stronger the storm. Storms caused by even the slightest gesture people do that makes she thinks “they are running away from me”. And thus a series of drama that alternate between “please stay with me” and “get the fuck out of my world”. The BPD doesn’t want anyone to leave, but she knows painfully well that if they do, there is nothing she can do to stop it. It’s obvious why BPD would want people to stay, but why are there difficult times that she just want to world to vanish and leave her alone? Well, it’s because when she start to realise that they want to leave her (or simple thought she realise that), she will – almost as a reflex – to compartmentalized the offending person. She don’t want to hurt herself over those people who want to leave anymore, and so she tries as hard as she can to push them out, to make them disappear from her world. Doing so while at the same time wanting them to stay will cause a great deal of pain to her. And the worst kind of pain too – psychologically. It hurts so bad that she have to find relief in cutting herself, partly to cause attention, but primarily because physical pain is much easy to bear with – you know where it hurts and how it can be stopped. There are some sort of biological process that apply a natural painkiller whenever the body is wounded, and it also have sedative properties. So by cutting or wounding herself, the pain inside becomes slightly easier to deal with and at least, it allows her to sleep.
To offending person though, a BPD is just straight up batshit crazy. She doesn’t understand what the hell is going on. All she ever did what saying or doing something that is perfectly normal yet the BPD just seems to be overreacting in every wrong way possible. And so, it is a lot easier for people to leave than to stay and deal with the mess that is the BPD. A BPD can have a crush on someone, and then go insane over all the little things they do ‘wrong’, thus pushing them away. Then she will find herself again, in the same old place, with a blade in her hand and cut marks on the other. She felt chills all over her body when she thinks about her crush. She wants to jump off the top of the building just to make it all go away. She doesn’t know how to live in this world. She never learn that the world doesn’t care about her. She never learn that the world doesn’t need her. She never learn that the only one who will be there with her, comforting her, holding her hands – is herself.