Bipolar Disorder vs. Borderline Personality Disorder
by Sam Matthews
Even though most people are aware that Bipolar Disorder and Borderline Personality Disorder are two different disorders, their differential diagnosis is often difficult due to many phenotypic overlaps between the two. Bipolar disorder often presents with three key features: mania, hypomania, and depression. It is one of the 10 leading causes of disability in the United States with a prevalence of 2.1% in the population. Bipolar disorder’s onset is usually during late adolescence or early adulthood, with cyclothymic temperament being the most common prodromal symptom. Borderline Personality Disorder, on the other hand, is categorized by impulsivity, instability in personal relationships, self-image, and affect. People with this specific personality disorder are often in problematic or chaotic relationships and become very suspicious, or even paranoid when faced with a stressful situation. This disorder can also present with depersonalization or dissociative symptoms, as well as suicide, or non-suicidal self-injury, which often leads to multiple hospitalizations during their lifetime. Their coping skills seem to be poorly developed and maladaptive, leading to even more problems in their daily life and relationships. About 15% of people living in the United States have been diagnosed with at least one personality disorder, however only 6% have one in Cluster B, which includes antisocial, borderline, narcissistic, and histrionic personality disorder.
When comparing the two disorders, it is imperative to make the distinctions as clear as possible. First, we can compare the suicide rates. For bipolar disorder, there is a 10% to 20% mortality rate from suicide, while there is an 8% to 10% mortality rate from suicide for those suffering from borderline personality disorder. Furthermore, bipolar disorder has an episodic course, meaning the symptoms come in waves, with different episodes of the disorder taking place over time. It is also categorized by gradual changes in mood (days to weeks). This differs from borderline personality disorder where the mood changes are often abrupt (hours). It is very common to see non-suicidal self-injuries in patients with borderline personality disorder, but uncommon in those with bipolar disorder, which could be why the suicide rate for those with bipolar disorder is double that of those with BPD. This is because those with borderline personality disorder have poor coping skills, and often want attention or just want to “feel something”, not actually die, due to their distorted way of thinking. Psychotic symptoms can be found in both disorders, however they are only present in bipolar disorder alongside the presence of mood symptoms, and only present in BPD during stressful situations. Another distinction between the two disorders is the way in which one develops it. Bipolar disorder has a genetic aspect, while BPD is usually caused by a significant history of trauma. Overall, these two disorders can often be confused due to the most obvious symptom: changes in mood, which is present in both, but it is important to look at both symptom profiles very closely when making a final diagnosis, in order to ensure that the course of treatment for the patient will be most beneficial and the greatest probability of a good outcome.