I was diagnosed with bpd in the mental hospital. The doctors there agreed I do not have bipolar II like I was previously diagnosed with, but I know bipolar is still on my file. I'm considering getting another assessment and looking to remove the diagnosis. I did not want a diagnosis of bpd due to the stigma but I have one now and I am tired of doctors worrying I'm going to get hypomanic on anti-depressants. DBT is effective for me, and lithium, depokate, and other bipolar meds made me worse. I think that's a clear sign bipolar ain't it, but if it is I'll have to deal with it. An assessment with a mention of every diagnosis I've received (there are many) is likely best. Fortunately more and more doctors are realizing it's a very treatable condition. The stigma is lifting, but it still exists, so be careful.
For me bpd is not an episode, but more of a state of being (it's classified as a personality disorder for a reason.) I do have co-occurring major depression. Those are episodes. I think bpd for me was a mix of genetic factors (I'm extremely sensitive and experience strong emotions, which is something that has been evident since early childhood and is considered a core bpd trait) and childhood trauma. I was never taught how to deal with my temperament, and was even scolded for it or taught it was a character flaw. Since I never learned how to deal with these emotions, it morphed into bpd. Well, that's my theory anyway. I ought to discuss this with a doctor or therapist.
I've heard fear of abandonment is the core of bpd, but that's not really the case for me. In fact, I wondered if I actually had bpd because I didn't think I feared abandonment and I like to be alone. I realized I do, and prefer solitude because then no one will leave me. I don't really fit the excessively clingy bpd stereotype. I am more likely to push people away to avoid abandonment rather than convince them to stay.
I think the fear of abandonment comes from the emotional liability aspect. I need someone to lean on to help me cope with my emotions, and I know my emotions make me hard to handle, so I worry people will leave me constantly. It is- once again- why I choose to remain by my lonesome, as it prevents abandonment entirely, and I'm convinced it will happen eventually, so why even form a relationship? It also leads me to be with toxic people who I know will never leave me, which causes unstable relationships. So do the mood swings, as I flip on a dime (idealization and devaluation.)
My emotional liability makes me more sensitive to stress, and more impulsive. I experience inappropriate outbursts due to my intensity. Quitting jobs, shoplifting, self harm, suicide attempts, substance abuse, reckless sex, binge eating: these were all coping skills for my emotions that I relied on because they were instant gratification and I just couldn't take the pain so why do healthy things? It's too hard and not as immediate as self-destruction. The mood swings also lead to an identity confusion. My feelings changing like the wind also leads to me questioning myself. My identity is tied to my emotions.
Do look into ADHD. I would argue ADHD is under diagnosed in women, whereas bpd is overdiagnosed (unless you're a minor or aren't difficult; then you're bipolar II.) although it's not in the dsm V, it's been established that emotional dysregulation is the core of adhd, and impulsivity is a symptom. The conditions have a lot in common. The two are commonly comorbid (I think that's the case for me, but once again I ought to get an assessment to know for sure, but adhd was diagnosed at ten and it's been suggested I get tested for adult adhd as well.)
TLDR; emotional dysregulation is a bitch. Distress tolerance is a skill taught in dbt for a reason.