Instability in a variety of areas, including interpersonal relationships, behavior, mood and self-image. Interpersonal relationships are often intense and unstable with marked shifts of attitude. Frequently there is impulsive and unpredictable behavior which is potentially physically self-damaging. Mood is often unstable with marked shifts from normal mood to dysphoric mood or with inappropriate intense anger or lack of control of anger. A profound identity disturbance may be manifested by uncertainty about self-image, gender identity, long-term goals or values. There may be chronic feelings of emptiness or boredom or brief episodes of psychosis..
A mood or personality disorder which affects more women than men. Where bipolars swing up and down, borderline personalities swing between love/amorousness and hate/anger. Because no one remembers anymore what "borderline" meant (an illness that wasn't quite schizophrenia), future editions of the DSM may call it Emotional Instability Disorder which should confuse it very nicely with bipolar disorder, formerly known as manic-depression. It is possible to have both borderline disorder and bipolar disorder.