In my experience in treating those with symptoms of Borderline Personality Disorder (BPD)- there is usually some form of a trauma history. Most consistently, I have found emotional abuse to be present. The presence of some form of abuse creates the maladaptive coping skills that define BPD. More significantly, invalidation, unsupportive environment and neglect form the lack of self or self-identity. At its core, I see BPD as an identity issue and when we are not validated in our most formative years- we do not know who we are as adults.
Research does indicate that there is a relationship between child abuse and borderline personality disorder (BPD). People with BPD report high rates of childhood sexual abuse, emotional abuse, and/or physical abuse. So, while there is a good deal of research that links childhood abuse to BPD, there is also evidence that about a third of people with BPD report no abuse.
While these studies are important in looking for causes that may be preventable, they are also helpful in determining how treatment may help people currently coping with the disease, in particular, approaches involving emotion regulation. I want to note, from a research perspective- there is correlation between childhood abuse and BPD but no causation.