Lucy, I've only just seen this thread and there are so many posts that I can't read them all in detail now. I just wanted to add my twopenceworth because I have experience of PBD. My DD2 was diagnosed with it after a troubled time during which she repeatedly self-harmed, attempted suicide and battled with anxiety and depression which were both crippling at times. I struggled to cope. She had psychotherapy which was worse than useless and twice we nearly lost her after two major suicide attempts (no dismissive remarks about attention-seeking, please, anyone, we've heard it all before!)
She managed somehow to complete her schooling and get a degree even though her final year was mostly spent in hospital - but she was determined to finish. She had a therapy called CAT while she was at university and that began to help, but it wasn't possible to continue once she'd left and returned home. It was years later - after somehow driving herself forwards extremely bravely to get an MA, travelling to Romania for a work placement for a couple of months and organising work experience for herself - she managed to get a place on a DBT programme whnere she lived in Islington. This is Dialectical Behavioural Therapy and aims to give coping skills and strategies to help equip sufferers for when their emotions overwhelm them (a big symptom) and to tackle risky self-harming behaviour patterns, amongst other things. It was intensive, but she did it and within weeks was beginning to feel benefits.
Roll on a few years and she is now living with a wonderful, loving and caring partner (I should also add that she has a disability but lives well despite it and her partner sees past it) and has a beautiful little baby girl -and she is a brilliant, loving and nurturing mother. I say that so that you can know that these things are possible, and that a diagnosis of BPD doesn't mean it defines you.
She will never be 'cured' as such: she still has what we call 'borderline moments' when her emotions overwhelm, but now she is able to deal with them far better and knows they will pass.
Her mother is a different matter (yes, that's me!) I have had anxiety and depression on and off for decades, as afar back as I can recall. It was only recently that a possible diagnosis of BPD was made. I have SOME of the symptoms but by no means all - no risky behaviour or self harm, for instance, but my emotions as often overwhelming and I find it hard to deal with them. And I relate to the jealousy'envy thing because for me that is huge, and I am deeply, deeply ashamed of this.
I was referred for another therapy: Mentalisation-Based Therapy. This, a psychotherapy based programme, lasts for 18 months, two days a week. I stuck it out for 9 months and gave it my best shot. I hated it, felt patronised, that I was a fish out of water and though I hate giving up on something, I had to admit to myself that it wasn't helping but actually making me feel worse. It encourages you to 'buy into' your emotions and give them creedence, which is not helpful for me - and I imagine, others too. What IS helpful is the ability to stand back from them, not run away or avoid, but learn to accept them as they are - just feelings, which will pass, but which probably don't have the awful significance our minds tell us they have.
I still dont' know whether the diagnosis is correct for me: as others have stated, it's only as good as the treatment offered. DBT has a Mindfulness element in it which is VERY important in treatment. I am working through a Mindfulness programme by myself but I would recommend DBT very highly and urge you to ask about a referral, if it's offered in your area. It changed my daughter's life completely.
I'm sorry this is so long and I hope bits of it are helpful. I wish you and your daughter every good wish - I know what it can feel like, both as a mother and a sufferer. 