here is what i think BP is, and it's cure (and i think you dont need therapy or pills to fix your problem, all you need is to be happy)
borderline personality is caused by constant stress over one thing, usually a relationship problem and it makes you back out at the first opportunity of failure because of obsession over things not going right. eventually everything seems black and white over the problem, where white is something positive about the problems and black is something negative contributing to the problems
the best way to fix it is to do things you don't want to do, such as helping others. being respectful to others by giving, and remember you have to give before you can recieve. because while your busy thinking about one problem that wont go away, everything else doesn't seem to matter and soon the world seems like it revolves around your happiness which you can't fulfill on your own, which in turn brings everything down until you cant take it anymore.
i learned the best thing to do is to do something you don't enjoy doing (that you say sucks but it ends up not sucking) like going out of your way to hang out with friends, or doing something you really hate like cleaning or maybe possibly watching tv which really helps change your mindset. easy decision seem to be always within reach, and always seem like common sense, and most easy decision making usually takes up time saying "that sucks, lets not do that" and "well lets just do this" and pretty soon everything sucks except a few things and eventually your down to impulse decisions based on what sucks and what doesnt suck and before you know it everything sucks so the best think you can do is start to do things you hate the most, and soon you will find that the things you used to enjoy in life are alot more enjoyable and you will be able to be happy and also regain your social life and happiness.
doing something you hate gets rid of the "everything sucks except what i get out of the situation" and makes things you hate doing dissappear until you are fully happy. like if you had to do labor every day for a week and then relax for a week, you would be thankful for that relaxation and soon would be able to manage time better and be able to plan good things for yourself. but without the labor you could not have relaxation and enjoy it. anyway i hope this helps because it's what im doing and i have my personality back and i'm happy and i'm no longer stressed and i'm starting to feel alot better about myself, which is ######6 great.