Borderline personality disorder (BPD) and bipolar disorder are two different mental health conditions that can cause significant distress and impairment in a person's life. They are also not as widely understood and destigmatized as other mental health issues. In recent years, public awareness about anxiety and depression has increased significantly—not so with BPD and bipolar disorder. More education about these two conditions is therefore critical. When more people know that BPD and BD are treatable medical issues, they’ll be more likely to seek help from a psychiatrist before the outcome is more serious.

What Is Borderline Personality Disorder (BPD)?

BPD is characterized by instability in a person's relationships, self-image, and mood. People with BPD may have extreme mood swings, difficulty with relationships, and a tendency to act impulsively. They may also fear abandonment and may engage in self-harm or suicidal behavior.

Living with borderline personality disorder is a bit like being on an emotional roller coaster with intense emotions, such as anger, depression, and anxiety, that can quickly change. You might do things impulsively, like spend a lot of money you don't have or drive recklessly, which can be harmful.

Maintaining stable relationships can be challenging for someone with this condition, and they are often scared of being abandoned or left alone. They can also struggle with how they see themselves and might feel empty or don't know who they are.

Sometimes, people don't acknowledge they have BPD until something big happens, like going to the hospital because of their symptoms. BPD can sometimes be confused with other mental health problems, leading to the wrong diagnosis, such as bipolar disorder. 

What Is Bipolar Disorder?

Bipolar disorder, on the other hand, is a condition that causes extreme mood swings that can range from extremely high (manic) to extremely low (depressed). One of the important differentiating factors is that these mood swings can last for 5-7 days or weeks at a time. People with bipolar disorder may also experience periods of normal mood in between episodes of extreme mood. During these periods, one can feel increased energy and grandiosity, start multiple projects, make risky and impulsive decisions, and feel a decreased desire for sleep.

Similarities Between BPD and Bipolar Disorder

There are some similarities between BPD and bipolar disorder, such as mood swings and impulsive behavior. Both mental illnesses can also have physical symptoms. (Here are some physical symptoms that can occur with bipolar disorder, for example.)

Another shared feature of BPD and bipolar disorder is the challenge of managing emotions. Loss of emotional control is a central characteristic of BPD and can come into play with bipolar disorder. As the National Institute of Mental Health defines BPD on its website, BPD “severely impacts a person’s ability to manage their emotions.”

With bipolar disorder, feelings can occur with greater intensity and fluctuation. Two common symptoms of bipolar disorder are anger and irritability. Their onset can happen suddenly and with little rationale for the person with bipolar disorder, and that can compromise the person’s capacity for emotional self-regulation.

What Are the Differences Between BPD and Bipolar Disorder?

There are also significant differences between BPD and bipolar disorder.

Mania and Mood Swings in Bipolar

One of the specific symptoms of bipolar disorder is manic episodes that last for at least 5-7 days. Mania is a symptom specific to bipolar disorder and is characterized by elevated or irritable mood and increased energy and activity levels. During a manic episode, a person with bipolar disorder may feel euphoric, have racing thoughts, and engage in risky or impulsive behavior. They may also have difficulty sleeping and may feel unusually talkative or have a decreased need for sleep.

Mania is not a symptom of borderline personality disorder (BPD), on the other hand. People with BPD may have extreme mood swings, but these are typically not as severe or as long-lasting as the manic episodes that occur in bipolar disorder. Instead, mood swings in BPD tend to be shorter in duration and may be triggered by events or situations in a person's environment.

Instability in Relationships, Self-Image, and Mood in BPD

BPD is primarily characterized by instability in a person's relationships, self-image, and mood, while extreme mood swings primarily characterize bipolar disorder. People with BPD can be hypersensitive to rejection and turn to self-harm behaviors when they perceive they are being rejected.

Other Differences, Including Treatment

There are other differences between BPD and bipolar disorder, relating to their causes, the behaviors associated with them, and what treatments can help relieve the symptoms. That makes it essential to get a proper diagnosis from a mental health professional—a specialist if possible—to determine the specific diagnosis.

While there may be some overlap, medications that help treat BPD generally are not effective for bipolar disorder and can even cause harm. The two conditions may also benefit from different therapies. For example, dialectical behavior therapy has a track record for treating BPD, having been developed for that purpose. Bipolar disorder may benefit more from cognitive behavioral therapy.

Rates of misdiagnosis are far too common with BPD and bipolar disorder, with sometimes tragic results. Those who are more fortunate often only learn they have BPD or bipolar disorder after they have been hospitalized. We can do better.