While bipolar disorder (formerly manic depression) and borderline personality disorders share some clinical features-primarily unstable moods and impulsive actions--they are two different diagnoses with different treatments (although psychiatrists may use medications to treat BPD as well as bipolar). They're even categorized differently in the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR). Bipolar is grouped in Axis I, clinical syndromes, and BPD is parked squarely in Axis II, personality (at least for now).
Yet that doesn't keep them from getting confused. Anecdotally, many family members tell me their loved one has been diagnosed with bipolar by a clinician when it appears to them that borderline personality disorder as described in the DSM-IV-TR seems to be a much better fit.
Now we've learned there may be more to this than a simple confusion.
A study from Rhode Island Hospital has shown that a widely-used screening tool for bipolar disorder may incorrectly indicate borderline personality disorder rather than bipolar disorder.
In the article that appears online ahead of print in the Journal of Clinical Psychiatry, the researchers question the effectiveness of the Mood Disorder Questionnaire (MDQ). The MDQ is the most widely-used and studied screening tool for bipolar disorder. It is a brief questionnaire that assesses whether a patient displays some of the characteristic behaviors of bipolar disorder.
The research team interviewed nearly 500 patients using the Structured Clinical Interview for Diagnostic Statistical Manual IV (DSM-IV) and the Structured Interview for DSM-IV for personality disorders. The patients were also asked to complete the MDQ.
The research team then scored the questionnaires and found that patients with a positive indication for bipolar disorder using the MDQ were as likely to be diagnosed with borderline personality disorder as bipolar disorder when using the structured clinical interview.
Further, their findings indicate that borderline personality disorder was four times more frequently diagnosed in the group who screened positive on the MDQ.
Principal investigator Mark Zimmerman, MD, director of outpatient psychiatry at Rhode Island Hospital, says that these findings raise caution for using the MDQ in clinical practice because of how differently the disorders are treated. (You can find more info here: http://www.eurekalert.org/pub_releases/2010-03/l-iir032510.php)
BPD and bipolar are often misdiagnosed as each other. Some people diagnosed with BPD actually have bipolar; the reverse is also true.
While only a qualified clinician can make a diagnosis of one or the other (or if both are present) there are three simple ways to distinguish bipolar disorder from borderline personality disorder.
Bipolar disorder causes dramatic mood swings, from overly "high" and/or irritable to sad and hopeless, and then back again, often with periods of normal mood in between. Severe changes in energy and behavior go along with these changes in mood. The periods of highs and lows are called episodes of mania and depression.
A cycle is the period of time it takes for a person to go through one episode of mania and one of depression. The frequency and duration of these cycles vary from person to person, from once every five years to once every three months. People with a subtype of bipolar (rapid--cycling bipolar) may cycle more quickly, but much less quickly than people with BPD (shifts can even last minutes/seconds).
According to Dr. Friedel, director of the BPD program at Virginia Commonwealth University, there are two main differences between BPD and bipolar disorder:
1. People with BPD cycle much more quickly, often several times a day.
2. The moods in people with BPD are more dependent, either positively or negatively, on what's going on in their life at the moment. Anything that might smack of abandonment (however far fetched) is a major trigger.
3. In people with BPD, the mood swings are more distinct. Marsha M. Linehan, professor of psychology at the University of Washington, says that while people with bipolar disorder swing between all-¬encompassing periods of mania and major depression, the mood swings typical in BPD are more specific. She says, "You have fear going up and down, sadness going up and down, anger up and down, disgust up and down, and love up and down."
Author, "The Essential Family Guide to Borderline Personality Disorder: New Tips and Tools to Stop Walking on Eggshells"
(Available at www.BPDCentral.com)