Are there times when you just can’t seem to push an unpleasant thought out of your head no matter how hard you try? Perhaps you thought you said something friendly to a person you didn’t know very well. Much to your chagrin, this person told you to mind your own business. Do you really lack interpersonal skills? Wow, you think. What have I not realized about myself until now? Days later, you still can’t shake off the whole encounter.

This dwelling on the unpleasant remark, known as rumination, is not that uncommon. Psychologists who study this process have found that if it’s persistent, though, it can serve as a risk factor for an individual’s development of depression. Although most people will eventually move off this negative mental channel onto more satisfying thoughts, those who cannot may develop a chronically sad mood. Until recently, rumination was almost entirely linked to depression. A new study focusing on borderline personality disorder suggests that the process can have a broader impact on mental health.

Rumination in Personality Disorders

According to Mississippi State University’s Kren Kelley and colleagues (2024), the emotional dysregulation (loss of control) and unhappy moods of people with borderline personality disorder (BPD) are made worse by rumination. Indeed, rumination could serve as “a key cognitive mechanism contributing to the perpetuation of emotional and behavioral regulation difficulties.” The more individuals with BPD go over and over in their minds whatever negative thought has become triggered, the more they lose the ability to modulate their feelings and actions.

BPD, in the current diagnostic system (the Diagnostic and Statistical Manual of Mental Disorders [DSM]-5-TR), is one of four “Cluster B” personality disorders, or those marked by such symptoms as impulsivity, interpersonal difficulties, anger, grandiosity, lack of empathy, and aggressive behaviors. Antisocial personality disorder (ASPD), histrionic personality disorder (HPD), and narcissistic personality disorder (NPD) are the other three within Cluster B. Notably, and consistent with criticisms of the DSM-5-TR, these personality disorders can be difficult to separate from each other in the diagnostic process. Kelly et al. propose that perhaps they can be differentiated by comparing their ruminative tendencies.

As it turns out, rumination can take one of six forms, note the MSU authors. Distinguishing among these is important because each one could have its own relationship to one of the personality disorders believed to have links to rumination. The purpose of the Kelly et al. study was to determine whether this fine-tuning of the rumination category could serve a useful function in helping to capture diagnostic differences among the four Cluster B disorders. You can learn from this study not only rumination’s role in BPD but also its role in your own everyday well-being.

Probing Rumination’s Six Types

Using an online sample of 725 adults aged 19 to 77 years (average age = 42), the research team administered a series of well-validated clinical measures to assess the presence of Cluster B personality disorders. Sample items from the six rumination scales are shown here below (each is rated either from 1 to 4, or 1 to 5):

• Anger rumination (think of an anger-provoking situation): I have long-living fantasies of revenge after the conflict is over.
• Depressive rumination: I can’t stop thinking about how you don’t feel up to doing anything.
• Rumination on sadness: I have difficulty getting myself to stop thinking about how sad I am.
• Self-critical rumination: My attention is often focused on aspects of myself that I am ashamed of.
• Rumination on interpersonal offenses: I can’t stop thinking about how I was wronged by this person.
• Worry: Once I start worrying, I cannot stop.

Turning to the findings, the authors were able to establish significant associations among the rumination types and personality disorder scores. Specifically, BPD was strongly related to anger rumination, but so were ASPD and HPD. This overlap argues in favor of critics who maintain that the categorical personality disorder approach is misguided. In terms of the Cluster B constellation of symptoms, though, as the authors conclude, “anger rumination [is] a probable transdiagnostic cognitive process contributing to the presentation of Cluster B personality pathology.”

BPD alone seemed to be related to self-critical rumination, a finding the authors did not expect. They believed that people high in this form of rumination would be more likely to show ASPD symptoms. Perhaps by including all four Cluster B personality disorders in this one study, this controlled for any independent contributions of ASPD. Depression rumination alone was associated with BPD, suggesting a new avenue of understanding this disorder. The other three personality disorders were, instead, associated with sadness rumination. Lack of worry, rather than rumination, was associated with higher ASPD scores, a finding that makes sense given that lack of remorse is such a key feature of psychopathy. NPD and HPD scores, though, also were associated with lower worrying. Perhaps surprisingly, rumination about interpersonal offenses had no relationship to personality disorder scores. The authors suggest that constantly going over feelings of being wronged could be part of the other forms of rumination.

Overall, the authors concluded that “aspects of negative thinking contribute to common forms of clinical impairment regardless of diagnosis.” In other words, the lack of discrimination among the Cluster B disorders argues in favor of allowing rumination to serve as the basis for “universal treatment interventions.”

Letting Go of Rumination

Now that you were able to explore the various types of rumination, as well as see how they could help explain this set of personality disorders, it may be easier for you to see how you could change your own patterns of negative thinking. Maybe you never considered before the difference between going over a critical comment versus not being able to stop worrying about how others feel about you. Identifying the ruminative type that fits your most common pattern is key to putting it behind you. Then, the type of “universal” treatment that could help people with personality disorders could, if translated into actions you could take, help you pull out of your own infinite loop of distressing thoughts.

To sum up, ruminative thoughts can easily invade your mind. By knowing what forms they take, you can be on your way to turning your thoughts to more fulfilling and productive patterns.