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Splitting in Borderline Personality Disorder

Three ways splitting can negatively impact romantic relationships.

Key points

  • Splitting behavior is a primitive defense mechanism to feel "safe” when feeling threatened, scared, or feeling judged or misunderstood.
  • Splitting is not limited to persons with BPD, but can be seen in people with pathological narcissism.
  • Splitting cannot be prevented, but there are key skills that can be learned to identify it in its early stages that can help with coping.
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Personality is identified by our lived experiences, our inherited traits, and our environment. Our personality traits include both genetics and personal experiences. How we engage with our environment, how we think, what we feel, and our outward behavior are a combination of these factors.

Sometimes personality can become malformed during key developmental stages in our lives due to adverse conditions, abuse, childhood trauma, neglect, or invalidation. Some of these malformations can cause personality disorders, including borderline personality disorder (BPD). According to Linehan (1993), invalidating a child’s lived experiences is one of the biggest predictors of developing BPD and the behaviors associated with it.

Understanding Splitting

One behavior that is seen in persons with BPD is “splitting.” Splitting is based on alternating between extremes of idealization or devaluation, all or nothing, and good or bad. The main problem with splitting is that the way a person sees the world is distorted and minimized to a “... you’re either with me, or you’re against me” mindset.

In people with BPD, splitting behavior is based on fears of rejection or abandonment to prevent feeling hurt. It’s a self-protecting primitive defense mechanism that helps them feel “safe” when they’re feeling threatened, scared, judged, or misunderstood.

However, splitting is not limited to only persons with BPD, but can be seen in people with pathological narcissism. Key differences include the function—or underlying motivation—of splitting behavior, based on diagnostic criteria. For example, people with pathological narcissism may split on a partner if they see themselves as “better than” (grandiose) the other person or may view themselves as more powerful than others in their life (dominance), which may be paired with coercive control during devaluation.

Splitting creates tension in romantic relationships, which typically includes chaos, conflict, and impulsive behavior, especially when a person has been “triggered.” It’s common for those with BPD to see their partner in the best possible light during idealization, and then to dramatically and often impulsively shift to seeing them in the worst possible light during splitting.

One of the hardest things to cope with regarding BPD is the feeling of shame and self-loathing that can come from putting their partner on a pedestal—only to “flip” to devaluing them when that person can’t live up to their expectations. These feelings of self-loathing and shame often trigger a cycle of self-sabotage and further self-loathing.

Splitting Behaviors in Romantic Relationships

Three common splitting patterns seen in intimate relationships can include:

1. Forgetting the Positive Qualities in a Partner. Splitting happens impulsively. When a person with BPD ignores the positive qualities in their partner, it’s often because they’re ruminating on negative qualities as a result of the splitting. In essence, when splitting occurs, any positive feelings a person with BPD has for someone may be replaced with disgust, animosity, and even hate. For example, if their partner shows up early for a date, they may be idealized as caring and wanting to spend more time with them. However, if the same partner got stuck in traffic, they may be devalued and seen as uncaring or rejecting.

2. Extreme Anger That Can Lead to Cognitive Distortions. Cognitive distortions may include impulsive decision-making, clouded judgment, dichotomous thinking, jumping to conclusions, paranoia, or dissociation. For example, if a partner has been devalued and split by a person with BPD, they may deny that their partner got them a birthday gift. Instead, they may engage in distorted thinking, or making wild accusations that they never received the gift, or that it was purchased for someone else. A natural reaction would be to show the person a receipt or photos as proof of the gift. Yet, these may be seen as “challenging” or “testing” a person with BPD, which may only make things worse.

3. Impulsive or Self-Sabotaging Behavior. If a person with BPD has devalued their partner, they may engage in self-sabotaging behavior such as bingeing on drugs or alcohol, or impulsively replacing the person with someone new. It should be noted that persons with BPD engage in impulsive (and counterintuitive) behavior as self-protective. For example, their partner asking for space may trigger distortions of thought (fears of being abandoned, paranoid ideation, or clouded judgment) where they may impulsively discard the person. However, once the dust settles from the impulsive behavior, many with BPD often experience deep shame and self-loathing where self-sabotaging behavior is then inwardly directed at themselves.

Can Splitting Be Prevented?

Because splitting is a primitive defense mechanism that is based on “survival mode,” it cannot be prevented. However, skills can be learned and implemented to help a person with BPD to start seeing reality in fewer absolutes, and with more flexibility.

Challenge the Misbeliefs or Dichotomized Thinking. A common pattern is to impulsively run with devaluation/splitting without challenging these messages. However, one way to challenge "all or nothing" thinking is by reframing thoughts by recognizing when words such as "only" are used, and changing them to "sometimes." Other suggestions can be to label several ways a problem may be solved by examining both sides of an argument or situation.

Recognize Deeper Issues. Is this person or situation really “all bad,” or could the outward splitting behavior be suggesting deeper issues in play such as feeling unsafe, or fears of abandonment being triggered? Many times, safety needs (consistency, trust, or predictability) have gone unmet or were not met consistently in childhood for persons with BPD. A betrayal of their safety needs in childhood can leave them vulnerable to feeling unsafe, such as being easily "triggered" or reactive. As a result, common relational disagreements can trigger devaluation unless things remain "perfect" in the relationship.

Practice the Pause. Splitting cannot be prevented, but there are ways to recognize if splitting is happening. For example, pause and take notice of what is happening in the environment that may be triggering dichotomous thinking, such as using words like, “always,” “never,” “everything,” or “nothing.” If a person can recognize what is happening environmentally, they can then begin noticing how the environment may be affecting their thoughts, feelings, and behavior, so that a healthier shade of "gray" can be integrated into the situation.


Day, N.J.S., et al. (2021). Pathological narcissism: An analysis of interpersonal dysfunction within intimate relationships. Personality and Mental Health, 16(3), 204-216.

Linehan, M. (1993). Cognitive-Behavioral Treatment Of Borderline Personality Disorder. New York: Guilford Publications.

Muñoz-negro J, et al. (2019). Paranoia and risk of personality disorder in the general population. Personality and Mental Health, 13(2), 107-116.

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