What's the difference between bipolar disorder and "Borderline Personality Disorder"?

What is "borderline personality disorder", anyway?  (I hate that term; I always want to put it in quotes to suggest that it does not merit the same consideration as a "diagnosis" as our other labels.  However, I must admit, the other labels have their problems as well. Maybe we ought to keep them all in quotes!). For a basic description, go to a well recognized expert's 2 -paragraph summary.  Here's a brief presentation about the "DSM" and current diagnostic rules.  For a question and answer format where a lot of folks with symptoms write in, and a very thoughtful therapist writes back, try this site:  there are good examples of both symptoms and therapy principles.  And for an extensive list of articles, all linked, see Dr. Ivan Goldberg's borderline materials.  But if you still wonder about the relationship between "borderline" and bipolar, read on. 

In the material below, you'll see the focus is on "how are they treated?" because presumably that is what diagnosis is supposed to be guiding.  Although generally very similar, there are two important differences in treatment.  In bipolar disorder, one uses antidepressants only with caution, whereas they are routinely used in the treatment of "borderline personality disorder."  Secondly, borderline treatment relies primarily on psychotherapy with medications coming second. Bipolar disorder is pretty clearly handled the other way around, with bipolar-specific psychotherapies coming second to medications (in general, no one advocates treating an average patient with bipolar disorder with psychotherapy alone). 

Yet the psychotherapy for borderline is not going to make bipolar worse, rather quite the opposite in most cases I think.  And the medications for bipolar disorder frequently make borderline better (including, in my experience, not just mood stabilizers, but also avoiding reliance on antidepressants in favor of an emphasis on mood stabilizers, in fact deliberately avoiding antidepressants at least for a time to see if that makes things turn out better).  So I arrive at the conclusion that trying to distinguish these conditions makes more trouble than it solves.  Have a look. 

Research on the Overlap of Bipolar Disorder and Borderline Personality Disorder

You may have heard about or even been told you are "borderline".  This used to be a very negative label, but now there's good evidence that specific treatment is possible and can help a  lot.^{Linehan et al, Meares}  So now the label is not as pessimistic and hopeless as it was even a few years ago.  On the other hand, Dr. Akiskal, one of the most outspoken researchers on bipolar disorder, often states that he does not believe "borderline" exists. Those who would like references on this point of view will find them in his rant against the borderline diagnosis from December 2004, online.
 A recent review from Canada found substantial overlap between borderline and bipolar disorder diagnoses, though still concluded that borderline deserved to be regarded as a valid diagnosis, separate from bipolar disorder.^Magill   This is an excellent review of this "overlap or one illness" issue, and I rather agree with the conclusion.  An online version exists, which is great, though it is in full doctor-lingo.  Another borderline research group, led by Dr. Gunderson who's been studying this phenomenon for decades, also warns against lumping the two conditions together, citing in 2006 interview his team's long-term observations of the two conditions.^Gunderson  He emphasizes the same differentiating factor I present in the next section: abandonment fear, prominent in borderline, not so in bipolar.
Although a recent opinion suggested that collapsing borderline into bipolar disorder would help both patients and doctors.^{Smith et al} , a nearly opposite point of view was expressed in the same journal issue^Paris , with an accompanying editorial overview.^Birnbaum To me the most interesting thing about these commentaries is that the authors presumably were examining the very same data, at least when they began the task, and yet derive opposite conclusions. When a very broad concept of bipolarity was used, 80% of patients with a diagnosis of borderline personality were found to have bipolar features.^Deltito  As a last relevant research study, here's one more: an Italian bipolar disorder specialist examined the specific symptoms found in bipolar disorder and in patients with "borderline traits" on a structured diagnostic interview.  He found that mood instability was common to both, whereas impulsivity was more associated with the borderline traits^Benazzi (although impulsivity has been characterized as a central feature of bipolarity by another research team ^Swann).
Interestingly, when a group of patients with a diagnosis of bipolar disorder was studied for "maladaptive personality traits", a substantial decrease was found when the patients' mood disorder was treated.^Peselow  Kind of makes you wonder if the same might be true for patients diagnosed as "borderline"?


The Overlap Between Diagnostic Criteria
There is tremendous overlap in the symptom patterns of bipolar and borderline personality disorder (Borderline PD).  The overlap reflects a basic problem with the concept of a "diagnosis" in the first place; for a brief essay on this topic, click here.  Notice in the table below that almost every symptom is found in each column:

Some doctors believe self-harm is "diagnostic" of borderline PD, or worse yet, synonymous:  all borderlines cut, and anybody who cuts is borderline.  It's hard, let me tell you, to convince them it isn't that simple.  Read one of the very helpful websites on self-harm if you need more information on this common behavior.
However, I think there is indeed one symptom that differentiates the two (to the extent there's any point in doing so; more on that in a moment).  You noticed the big yellow blank in the table, yes?  People with profound fear of abandonment, and a feeling of chronic emptiness, have a different struggle in life from those who don't have these problems.  Recently one of the most prominent borderline specialists, Dr. Glen Gabbard, emphasized these symptoms as the core of "borderline" experience.^Gabbard
In my practice, I've had patients who do not have chronic emptiness or abandonment fears who do have self-harm behaviors, which show up when they are extremely agitated.  These patients all seem to have figured out that cutting or other forms of self-harm (I had one patient who hit herself on the head with a rolling pin) somehow helped them cope with the intensity of the rest of their symptoms.  I have no doubt now that self-harm behaviors are an attempt to "treat" the severe agitation somehow; but that behavior seems rather quickly to disappear when the agitation is controlled.


Treatment
There are good treatments for both conditions.  Borderline PD is usually treated with psychotherapy as the main tool, with medications as needed or to the extent that they are helpful.  Bipolar disorder is treated just the other way around: start with medications as the core ingredients in treatment, but using psychotherapy wherever it might be helpful.
Medications
All of the medications we routinely use in treating bipolar disorder have been shown in published studies to have some value in borderline PD^Soloff: antidepressants, mood stabilizers, and antipsychotics. (The mood stabilizers and modern antipsychotics are all presented, each with a page of details on benefits and risks, on my mood stabilizer list page). Here are some of the studies:

At least two studies have been published both showing that "borderline personality disorder" patients respond to Depakote^{Hollander ,Frankenburg}.  A pair of recent studies showed response to Zyprexa was greater than to placebo.^Bogenshutz,^Zanarini  A small randomized trial showed lamotrigine was better than placebo in patients with borderline diagnoses.^Reich  Similarly, a research team looked back at "borderline" symptoms in the pair of large lamotrigine studies for bipolar patients, and found that "borderline" symptoms appeared to improve along with the bipolar symptoms.^Preston 

Most recently, aripiprazole has also been shown to be better than placebo for patients with borderline personality disorder.^Nickel  Lithium has not been studied in a controlled trial in borderline personality disorder, but is advocated for "targeting specific symptom domains" such as mood instability; I did not find anything newer about lithium than the old review by Soloff in 1994, which also includes a review of the use of carbamazepine in borderline.  

Therefore it seems even safer now than several years ago (when I first wrote this essay) to say that "mood stabilizer" medications typically thought of for bipolar disorder are also worth thinking of in borderline PD.
Psychotherapy
The best studied technique for borderline personality disorder is "dialectic behavior therapy", designed and studied initially by Dr. Marsha Linehan.  Here are some descriptions of this approach:  brief; technical; simpler but more information. This technique is distinguished from the approaches which proceeded it in (at least) three ways:

• It has randomized-trial evidence for effectiveness; 
• It has an understandable, logical, research-oriented rationale behind it. 
• It focuses on behaviors, and may not be sufficient treatment for feelings. 

A group in Europe used the Linehan treatment approach, and got the same results as in Dr. Linehan's original research^{Linehan et al}, namely a dramatic decrease in suicidal and self-harm behaviors, although they point out that the big improvements came for the patients with the most severe symptoms.^Verheul  They suggest that the Linehan DBT approach may be best suited for patient with severe self-harm and suicidal behavior, and that other therapies might be more appropriate for patients without these behaviors -- because DBT does not seem to affect mood symptoms very much.  Thus, there may be even more reason, supported by the Verheul study, to think about medications for mood, as well as psychotherapies for mood (after DBT for self-harm and suicidality, if present).

Written by http://www.psycheducation.org/depression/borderline.htm