When Symptoms Overlap

By Taylor Wolfenberger, B.S.A., M.D.-candidate, and Marsal Sanches, M.D., Ph.D.

Diagnosis in any area of medicine can be a complicated task. If someone presents to physician with a cough, that cough could be caused by a variety of illnesses. Mental health is similar in that the same symptom can be present in multiple disorders.

Symptoms have to be parsed out and explored because there are subtle nuances that need to be understood in order to have a proper diagnosis. One area where people often get confused is with the symptoms of borderline personality disorder (BPD) and bipolar disorder (BD).

What is BPD and BD?
BPD is a mental health condition in which individuals have difficulty managing and regulating emotions, which leads to chronic instability in feelings, behaviors, and interpersonal relationships. Impulsive behavior (such as reckless driving, gambling, substance use, and excessive monetary spending) are common.

A defense mechanism commonly seen in BPD is a phenomenon known as splitting, by which a person may view something or someone as either all good or all bad due to difficulty reconciling conflicting emotions. In addition, individuals with BPD often experience an intense fear of abandonment and an unstable sense of self-identity. The fear of abandonment may lead the person to take extreme measures to avoid rejection or the dissolution of a relationship. Importantly, BPD is associated with an increased risk of self-harm and suicidal behaviors. Frequently individuals with BPD have a history of major trauma, often in childhood.

On the other hand, BD is a mental health condition in which an individual’s mood alternates between periods of depression and an abnormally elevated mood, called mania. The depressive and manic episodes can last for days to months.. The depressive phase of BD is characterized by sleep changes/disturbances, lack of interest in activities, feelings of guilt, low energy, concentration difficulties, appetite changes, restlessness or slowed movements, and/or suicidal thoughts or behaviors.

In contrast, manic episodes are associated with an elevated mood, irritability, distractibility, impulsivity, feeling “larger than life” or “on top of the world,” racing thoughts and ideas, agitation or increased activity, decreased need for sleep, and/or talkativeness. Individuals with BD can sometimes experience milder forms of mania (hypomanic episodes), which do not bring about significant functional impairment, despite clearly corresponding to a deviation of the person’s usual self. Of note, there are two types of BD (BD-I and -II), which differ by the degree of mania a person experiences.

How Do They Overlap?
Even though the differences between BD and BPD may sound straightforward, it can be difficult to distinguish the two conditions in real life. BD and BPD share several factors and there is not a laboratory test, brain imaging exam, or other workup tools to help clinicians with the distinction. Both conditions can significantly affect quality of life and relationships. Like BPD, BD can also present with impulsivity, an increased risk of suicidal behavior, increased rates of substance use, intense mood swings, low self-esteem, and depression. An additional complicating factor, from a diagnostic standpoint, is that both conditions are often associated: Twenty percent of patients with BD-II and 10 percent of patients with BD-I also have a diagnosis of BPD.

Despite the features that BD and BPD share, there are several important differences between the two conditions. BD is typically more episodic, with distinct depressive and manic episodes alternating for various lengths of time. There are usually periods in between such episodes in which a person’s mood is stable. While symptoms of BPD can also wax and wane to some degree, BPD is overall considered to be a lifelong pattern, with sudden, short-lived shifts in mood.

Given the numerous similarities between BD and BPD and the difficulty of distinguishing the two, it is important for people to receive a formal diagnosis from a mental health professional rather than self-diagnose.

Why Are Diagnoses Important?
The distinction between BPD and BD is important. As with many of the personality disorders, there has long been a stigma associated with diagnosis of BPD. Society and the media commonly portray individuals with BPD as unstable, manipulative, and unresponsive to treatment. However, these are misconceptions and can be extremely harmful. In addition to causing emotional distress, such labels may discourage someone with BPD from seeking treatment.

Research indicates that the stigma may also influence clinicians in their treatment of patients, leading some mental health providers to hesitate in diagnosing BPD. In light of the public perception of BPD, a diagnosis of BD can often be easier for patients to accept, as it is more widely accepted that BD is caused by a biological glitch within the brain that is treatable with medications.

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Personality disorders, on the other hand, are often portrayed as rigid, inflexible, longstanding patterns of thinking and behaviing that are resistant to treatment. A common misbelief about BPD is that the person is choosing to engage in volatile, attention-seeking, intentional acts. In reality, it is very difficult for an individual with BPD to adapt to new situations and express their emotions appropriately. In addition, while BPD has historically been viewed as difficult to treat, much of the data in recent years has shown that BPD can in fact be managed successfully with dialectical behavioral therapy. (DBT)

BD and BPD are also treated differently. The treatment for BD is most commonly mood stabilizer medications (such as lithium, valproate, carbamazepine, or lamotrigine) in addition to therapy. In contrast, while medications can be used in the treatment of BPD, the first-line treatment is DBT, a form of structured talk therapy that helps a person accept realities and find ways to regulate their feelings and behaviors.

Overall, it is critically important to be able to distinguish between BD and BPD, as proper diagnosis and treatment are essential to the management of both disorders. Combating the stigma surrounding BPD and other mental health disorders can create a culture that encourages people to openly seek care and receive appropriate treatment.

Taylor Wolfenberger, BSA, is an M.D.-candidate at the McGovern Medical School at The University of Texas Health Science Center, Houston. Marsal Sanches, M.D., Ph.D., FAPA, is a board-certified psychiatrist with the Adult Treatment Program at The Menninger Clinic, Houston, where he also is director of Research Education and director of Medical Student Education.