I'll try to give you a little insight into my own experience with a situation that is not altogether dissimilar (in a very general sort of way). This is just by way of providing you with an example, BTW, and I'm not necessarily making a direct comparison.

My marriage of 16 years is just now coming to an end, and I can't help but see a familiar pattern in the few details that you've provided. I loved, and do love, my (soon to be ex-) wife very much, and I know that she loves me. But (as I've written in my own posts), the harsh reality is that love alone does not simply "conquer" the difficulties of behavioral problems such as those that you outline. My own wife has suffered, for years, from OCD, anxiety & depression, and bouts with borderline personality disorder. She would, at somewhat regular intervals, display behaviors very similar to those that you describe: e.g., disproportionate levels of angst, inappropriate reactions, and a general, inexplicable aversion to rational problem-solving.

In the early phases of our relationship, we went through a lot of the same sorts of things, with her becoming upset and frightened over this-or-that (non)issue, breaking up with me, and then within a short time wanting to get back together. She always seemed so very sincere and kind in those "make up" moments, but the irrational fears and attendant anger that she would express were just as "real." Her behavior could be, at times, extremely erratic and alarming. She simply didn't have the ability to think ahead and consider the true ramifications of what she was doing in her moments of panic and confusion.

There's more to say about the underpinnings and nuances of this sort of behavioral illness, but I'll stick to trying to give you an answer to your question `does a person ever fully recover?' From my own perspective, I would say that I think that it is certainly not impossible for someone to "recover" from these problems. But it is extraordinarily difficult, particularly in the context of a relationship. Here's why: a person with behavioral problems stemming from the borderline personality disorder spectrum (which, for now, is the term that I'm nominally applying) is never going to get "better" unless they, themselves, truly recognize the problem and take their own steps toward recovery. And that can never happen if you are there to constantly "run interference" for that person by being the "fixer" in the relationship. By doing so, you will only be "enabling" a continuation and worsening of the irrational behavior. Believe me, I understand that you do this out of love, but it's not what the person needs.

She needs to be allowed to "fail," so to speak, on her very own terms and feel the full weight of the consequences of her own actions. That may sound harsh, but it isn't as bad as the fallout from enabling the behavior year after year. My guess would be that your girlfriend has come to see you (without even consciously knowing it) as a sort of "cushion" between her and the consequences of her behavior. When she experiences the inner emotional turmoil brought-on by her BPD-like mindset, she increasingly feels that she can lash-out and behave in any way she wants, because she knows that, eventually, you're going to come back around to "rescue" her.

The result, if it's allowed to continue, is a disastrous pattern of co-dependence that becomes harder and harder to break. If you want to love this person and experience a healthy relationship with her, then you've got to do something right now to break that pattern. Otherwise--no--she will not recover and things will only get worse. And your own sanity will also begin to slip, because you will slowly be trained to "accept" that love is a one-way street--i.e., that it's "wrong" to "expect" anything in return for your constant input of affectionate effort.

The pattern must be broken. That's the long and short of it.

I'll suffix all of this with the following caveats: again, I'm only giving you insight from my own, familiar-sounding situation, without knowing a lot of the details of yours. I could be completely off-base, and much of what I've pointed-out, here, may very well not apply at all. Also, please know that in no way am I writing these words in an effort to remove hope. There is always hope. Believe that. But know that it is very difficult and that if you do truly want the relationship to work, you've got to be strong and refuse to live someone else's life for them, no matter how difficult their situation and no matter how much you love them. They are better off solving their own problems. Show your unequivocal support, but do not fall into the trap of thinking that love is equivalent to fixing the mistakes caused by the one you care about.

Best of luck to you.