borderline of what?

[samj81]

This may seen like a silly question but the term borderline personality means what?is this refering to the split emotions they have meaning at different times they may seem like different people?if so is that not more like split personality?

Also my exBPD boyfriend used to meantion when he was "borderline" to what was he refering?is that like disregulating?sorry if i may sound dumb,im relativly new to this and researching as much as i can.

[TheDude]

The term itself originated in the 1930's, and implied the 'borderline' between neurosis and psychosis.

"Borderline personality disorder (BPD) is a diagnosis with an unusual history. The idea that patients might fall on some sort of “borderline” between psychosis and neurosis dates back to 1937, at which time the syndrome was first described."

www.ncbi.nlm.nih.gov/pmc/articles/PMC2922389/