a defence mechanism in which someone who can't cope with ambivalent feelings about others compartmentalizes those people as all good or all bad.
Involves dissociating positive and negative aspect of oneself and others, and compartmentalizing them into "all good" or "all bad" images. People who use splitting see themselves and others in black-and-white terms, dividing the world into "good guys" and "bad guys." Term also used when a resident asks one staff person for something, then goes to another staff person if answer is not what he or she wanted.
A mental mechanism in which the self or others are reviewed as all good or all bad, with failure to integrate the positive and negative qualities of self and others into cohesive images. Often the person alternately idealizes and devalues the same person. From a psychoanalytic point of view, splitting is fundamental to borderline personality disorder, and underlies the dramatic shifts in the person's experience of self and others and their difficulty in finding a stable adaptation to life.