Differences Between Bipolar Disorder and BPD

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Borderline personality disorder (BPD) has been a controversial diagnosis since it was first recognized in the Diagnostic and Statistical Manual of Mental Disorders in 1980. One controversy that still has not been resolved is whether or not BPD is related to bipolar disorder since they have many similar symptoms.

How Bipolar and Borderline Personality Disorder Are Similar

The primary reason that some experts have proposed that BPD and bipolar disorder may be related is that they share the common feature of mood instability.

Bipolar disorder is associated with mood shifts from depression to mania, a mood characterized by elation, a decreased need for sleep and an increase in activity, or hypomania, which is similar to mania but less severe.

BPD is also associated with mood changes, sometimes called emotional dysregulation or affective instability. People with BPD can frequently change from feeling fine to feeling extremely distressed in a matter of minutes.

Impulsive behavior is also frequently experienced both by people with bipolar disorder and by people with BPD.

How Bipolar and Borderline Personality Disorder Are Different

What is the difference between BPD and bipolar disorder, then? Some major components separate the two.

  • Quality: While the disorders are both characterized by mood changes, the quality of the mood changes can be very different. People with bipolar disorder tend to experience mania and depression while people with BPD experience intense emotional pain and feelings of emptiness, desperation, anger, hopelessness, and loneliness.
  • Time: In BPD, mood changes are often more short-lived. They may last for only a few hours at a time. In contrast, mood changes in bipolar disorder tend to last for days or even weeks.
  • Cause: Mood shifts in BPD are usually in reaction to an environmental stressor, such as an argument with a loved one, whereas mood shifts in bipolar disorder may occur out-of-the-blue.
  • Degree: The mood shifts typical of BPD rarely involve elation. Usually, the shift is from feeling upset to feeling OK, not from feeling bad to feeling a high or elevated mood, which is more typical of bipolar disorder.

Are Bipolar and Borderline Personality Disorder Related?

Although it is not yet clear-cut, research has not found a strong relationship between BPD and bipolar disorder. There is some evidence that people with BPD are diagnosed with bipolar disorder at higher rates than individuals with other personality disorders.

One study found that about 20% of people with BPD are also diagnosed with bipolar disorder. Only about 10% of people with other personality disorders also have a bipolar disorder diagnosis.

Another study looked at people diagnosed with both BPD and bipolar disorder within a 10-year timeframe. The results showed that the disorders appear to be completely independent. The study's authors stressed that it's extremely important to treat each disorder individually for the best chance of symptom relief.

The Bottom Line

So far, there is not enough research to suggest that BPD and bipolar disorder are related. Although there are definitely some shared features, there are also some marked differences between BPD and bipolar disorder.

Also, the co-occurrence of BPD and bipolar disorder is not large enough to suggest that the two disorders are related. However, more research is needed on this topic. It may be that future research, for example, on the genetic and biological causes of BPD and bipolar disorder, may reveal some undiscovered relationships between the two conditions.

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  • American Psychiatric Association. Diagnostic and statistical manual of mental disorders, 4th ed, text revision. Washington, DC, Author, 2000.
  • Gunderson, J.G., Stout, R.L., Shea, M.T., et. al. "Interactions of Borderline Personality Disorder and Mood Disorders Over 10 Years." The Journal of Clinical Psychiatry 75 (8), 2014.
  • Gunderson JG, Weingberg I, Daversa MT, Kueppenbender KD, et al. "Descriptive and Longitudinal Observations on the Relationship of Borderline Personality Disorder and Bipolar Disorder." American Journal of Psychiatry, 163:1173-1179, 2006.
  • Paris, J. "Borderline or Bipolar? Distinguishing Borderline Personality Disorder from Bipolar Spectrum Disorders." Harvard Review of Psychiatry, 12:140-145, 2004.

By Kristalyn Salters-Pedneault, PhD
 Kristalyn Salters-Pedneault, PhD, is a clinical psychologist and associate professor of psychology at Eastern Connecticut State University.