I’m posting this here in the hopes of gaining some sort of insight into my girlfriend's mental state, and possibly figuring out what sort of treatment she should get (or just being directed to the right forum). If someone could take a stab at diagnosing her with something specific, that would be helpful.

Lucy and I have been in a relationship for a little over two years, and we moved in together about eight months ago. I’m a pretty level-headed and reasonable sort of person, and I rarely even raise my voice at anyone, but Lucy has become -- at least around me -- the near-complete opposite. She’s been this way to some degree or another since I’ve known her, but her behavior has become increasingly troubling to me since we began living together.

It is difficult to partake in even the most basic of activities without her stirring up some sort of needless dramatics and becoming extremely emotional. She recently had a near-breakdown over being a few minutes late for a reservation. She will become unhinged over things like debating with me on which restaurant to go to, or what TV show to watch. Actually, it is near impossible to have any sort of debate/argument/disagreement with her, without her seeing the whole thing as a personal attack on her character or her views. If I bring up an issue with her regarding something she’s doing that I don’t like, her reaction is almost always to become defensive, hyperbolic (“You hate me don’t you! You hate everything I do”, that sort of thing), angry with me, or rolling-eyes dismissive, but typically more than one of these things in rapid succession. At these times, no matter how important the issue, it’s as if she’s literally incapable of saying “I apologize, I’ll try not to do that anymore”.

Her mood can change on a whim, and these changes are often extreme. For example, she might appear really upset about something, and then she’ll get a text, her face will change, she’ll laugh and completely dismiss what she was just upset about as if it had never occurred. At my sister’s wedding, she managed switch on a whim between being gregarious toward everyone and fuming at me for not wanting to dance to a particular song that had no major significance to either of us. She can veer from being extremely lovey-dovey toward me, to being angry at me for not loving her enough. Sometimes I wonder if she just plays up her emotions for dramatic effect. I feel like she craves something from it. I think it makes her restless to NOT stir up drama. She has literally said, in regards to certain aspects of her life: “I’m not getting what I need, so I act out”. So at the very least she is self-aware, just not willing to do anything about it, and possibly doesn’t even see anything wrong with that sort of behavior.

She has tremendous insecurities as well. Two years into the relationship, she is still constantly in fear of me breaking up with her, despite the fact that we’ve moved in together and have discussed in detail marriage/family. She has admitted to me in the past that she may have masochistic tendencies, and at times I feel like her behavior is all just one big act of self-sabotage on her life.

Does any of this sound like the symptoms of any particular disorder? I realize that some of it might come off as typical “relationship stuff” but believe me when I say that with Lucy, it’s all amplified to a point where if a third party were in the room, they’d be horrified at her behavior.

I have tried in vain to get Lucy to regularly see a psychologist, but she doesn’t feel that it helps her at all. She started taking adderall recently, but I don’t think this has had any major effect on her moods one way or another (no other drugs or major alcohol usage by the way). I feel like she gets part of this from her mother, who is, to put it mildly, an exhausting basket case of worry and negativity. I know that her mother took her to psychologists as a kid, and they thought she had some kind of personality disorder, but this was like 20 years ago (we’re both 30).

On a physical level, there’s nothing wrong with her, and there’s nothing unusual about her routine. She eats fine, exercises regularly, gets a normal amount of sleep. Her day-to-day is balanced. She works hard, comes home, tries to relax, does things on the weekend.

Part of what makes this situation so difficult is that she only acts this way around me and (to a much lesser degree) her mother. She puts up a very good front for her friends and in public. Her job involves a lot of interaction with other people, and she’s a complete professional and great talker 100% of the time. When I did briefly get her to see a psychologist, I got the sense that she appeared just as put-together to this psychologist as she does to everyone else around her. I am the only one who ever sees this negative side of her.

Being around Lucy is like walking on eggshells, and it’s really taking its toll on me. If there’s some kind of medication that would potentially “even her out” a bit, I want to get her on it. Anyways, any insights would be greatly appreciated.