Psychoanalytic theory suggests that the instability in emotions and interpersonal relationships seen in people with borderline personality disorder is due to:

The reason in which instability in emotions occurs and interpersonal relationships seen in people with borderline personality disorder is because of splitting. Splitting in psychology is being defined as having an individual of failing when thinking of bringing together the idea of qualities that are positive and negative in one’s self and towards others in which should be in a realistic whole.