Bipolar vs. Borderline

Photo by Dimitar Belchev

Many people are leery about the stigma of mental illness. They hesitate to seek professional help and do so only as a last resort. So, by the time they finally make it into treatment, they are anxious, demoralized, and bursting with questions. On top of the list of questions is usually one about diagnosis. Although it’s rare that I encounter patients who start the first meeting with a self-diagnosis, it does happen. And in these cases, one scenario stands out — that is, the individual believes he or she has bipolar disorder “because the mood can go up and down.” Isn’t that the definition of bipolar disorder?

No, it is not.

Bipolar disorder is a mood disorder. Its mood episodes can vacillate between the manic spectrum and the depressive spectrum. Even though the presentation is not always clear-cut and the severity and duration can vary wildly, the name bipolar suggests a certain rhythm to the illness. Perhaps because of the name, some people assume that if the mood goes through drastic changes — significant highs and lows; happy one minute, sad the next — then it must be bipolar. Not necessarily. Borderline personality disorder, for example, could be the underlying condition instead.

Borderline personality disorder is not a mood disorder, even though significant mood symptoms are frequently reported by the individual and observed by others. Rather, a personality disorder indicates an enduring pattern of inner experience — perception, self-image, world view, impulse control, boundaries — that is consistent across different situations and relationships. It implies a persistent way of thinking, feeling, and behaving that deviates from cultural expectations and often results in difficulties. People with borderline personality disorder typically struggle with a range of significant symptoms — impulsive or risky behaviors; intense and unstable relationships; frantic efforts to avoid abandonment; chronic feelings of emptiness; highly changeable moods; inappropriate anger outbursts; self-harming behaviors or suicidal gestures; even transient paranoid ideation or dissociative episodes. These symptoms can interfere with day-to-day activities, especially interpersonal dynamics.

Not everyone with borderline personality disorder will experience every symptom. But, by and large, these symptoms can surface whether or not there is a concurrent mood episode; in other words, these symptoms do not surface exclusively during an elevated period of mood or energy (i.e., mania) or depression.

Let’s take risky behaviors as an example. Risky behaviors such as spending sprees, unprotected sex, reckless driving, substance use, binge eating, etc., can be observed in both individuals with bipolar disorder and individuals with borderline personality disorder. However, for those with bipolar disorder, risky behaviors tend to occur while their mood is in an elevated state. The lack of insight coupled with a grandiose sense of self can lead to excessive risk-taking uncharacteristic of the individual. But when the mood is not in an elevated state, the risky behaviors scale back to normal. In other words, the untreated or undertreated bipolar disorder is the driving force behind the risky behaviors.

By contrast, people with borderline personality disorder may periodically engage in risky behaviors when their sense of self is challenged by real or imagined criticism or disapproval. At times it feels as if their sense of self and self-worth is not anchored; how they feel about themselves and others depends on their impression of either at that particular moment. Therefore, if they feel bad about something, that feeling becomes their sole focus and everything else falls by the wayside. As their mood spirals out of control, their judgment, impulse control, and decision-making can all be compromised.

Is it possible to have both bipolar disorder and borderline personality disorder? Yes, it is. But more often than not, it is one or the other and not both. Making a differential diagnosis is critical, as it will have significant bearing on what types of treatment to pursue. As always, temporary symptom relief is not sufficient. Understanding the etiology behind the symptoms will make the biggest impact down the road.