“Splitting” is a term that describes difficulty with the ability to hold opposing thoughts, feelings, or beliefs about oneself or others. In other words, positive and negative attributes of a person are not joined together into a cohesive set of beliefs.
Splitting is very common in people with borderline personality disorder (BPD), and it leads people with BPD to view others and themselves in “all or nothing” terms. For example, a person with BPD may view one family member as always “good” and another as always “bad.” Or, a person with BPD may see themselves as “good” one minute, but shift to seeing themselves as all “bad” or even evil the next.
Because of splitting, it is difficult for individuals with BPD to recognize that “good” people sometimes do things imperfectly or make mistakes. The experience of splitting is very confusing and frustrating for people with BPD and their loved ones. Splitting can interfere with relationships and work life, and can lead to intense anger and self-destructive behaviors.
American Psychiatric Association. “Practice Guideline for the Treatment of Patients with Borderline Personality Disorder.” American Journal of Psychiatry, 158:1-52.