What are the Differences Between BPD and Bipolar Disorder?

Understanding the Key Differences Between Borderline Personality Disorder and Bipolar Disorder

Making an accurate diagnosis is an art because there are many disorders that mirror one another with only subtle differences to tell them apart. Borderline personality disorder (BPD) and bipolar disorder are two conditions that look similar on the surface but are different underneath. What is the real difference between BPD and bipolar disorder?

Both disorders have mood instability, impulsivity, and frequent substance abuse. However, bipolar is characterized by manic and depressive episodes, while borderline personality disorder is marked by a pattern of unstable relationships and a fragile self-image. The causes and treatment of both diverge as well.

Catalina Behavioral Health can help you pinpoint an accurate diagnosis for both BPD and bipolar with a comprehensive assessment. We provide the right level of therapy and support to meet you where you are right now. Keep reading to learn more about the differences between BPD and bipolar.

What Do the Two Mental Illnesses Have in Common?

Before we dive into the differences between bipolar disorder and personality disorders, it’s important to understand why it’s so difficult to diagnose these two conditions. There are some features of both that are closely related, though a skilled mental health professional can tease out the differences.

Unfortunately, up to 21 percent of bipolar patients will also have borderline personality disorder, further complicating the diagnosis.

Here’s what they have in common on the surface and what differences you can expect to underlie these similarities.

Overlap in Mood Instability Between Bipolar and BPD

One of the reasons that it’s so difficult to diagnose bipolar disorder or borderline personality disorder is that they do have some overlap when it comes to moods. Both disorders come with varying degrees of mood instability, with the person diagnosed dealing with extreme mood swings.

If that’s the case, how can you tell the difference between BPD and bipolar disorder?

The difference lies in the triggers for the mental health issues seen in each. Bipolar disorder tends to have mood episodes that aren’t triggered by any one major event. On the other hand, a borderline diagnosis means that mood issues are triggered by a specific event, usually around interpersonal relationships.

The differences also surface in the length of time that these mental health disorders deal with the mood instability. Bipolar disorder mood episodes tend to last for days or weeks, while borderline personality disorder moods can last for minutes or hours in some cases.

Impulsivity and Reckless Behavior

Another common similarity between bipolar disorder and borderline personality disorder is the tendency to behave impulsively.

In bipolar disorder, those who are struggling with manic episodes often feel as if they’re on top of the world. This leads to lots of risky behavior because they can’t think through the consequences of their actions.

Borderline personality disorders have similar symptoms. People with this mental illness tend not to have emotional control or may be willing to act out due to a perceived threat of abandonment. Instead of being driven by a mood issue, they seek some sort of reward.

In both instances, you’ll see similar behavior: risky sex, impulsive spending, and reckless driving. But you have to dig deep beneath the surface to tease out the differences.

Substance Abuse in the Two Disorders

In addition to some of the other overlapping symptoms, it’s important to note that substance abuse and substance use disorders are common in both for similar reasons. In bipolar disorder, many people use drugs and alcohol as a way to control their mood episodes.

Alcohol, in particular, can be very effective at triggering manic or depressive episodes.

Borderline personality disorder requires a similar method to control impulsivity and mood swings. Many people will use drugs and alcohol as a means to cope with the discomfort of the ever-changing moods. It often becomes habitual when experiencing mental health issues.

Differences Between Bipolar Disorder and BPD

While there are a handful of areas where these two disorders converge, many more issues are notably different. Understanding the basic underpinnings of each disorder is key to telling them apart and getting the help you need in a clinical setting with a skilled therapist and psychiatrist.

Here are a few areas where these mental health disorders warrant a separate diagnosis and more tailored treatment plans.

Depressive Episodes and Manic Episodes in Bipolar Disorder

One of the main differences between the two diagnoses is that bipolar disorder has distinct mood episodes compared to the intense mood swings of borderline personality disorder. Bipolar patients experience two distinct mood states when they aren’t in a period of euthymia (no mood states).

Manic episodes are marked by high-energy states, a typically euphoric mood, and impulsivity. On the flip side of the coin, they are often followed by depressive episodes where the person doesn’t want to do much of anything. The episodes tend to last weeks to months rather than hours or days, as in BPD.

Understanding the hallmarks of a manic episode and tracking its patterns can often lead to an accurate diagnosis of bipolar disorder over BPD.

Focus on Relationships in BPD

While bipolar disorder is characterized by mood swings between manic highs and depressive lows, BPD has a different focus. This mental health condition is usually marked by issues with close relationships and an unstable self-image. People with borderline personality disorder tend to want people close to them but later push them away.

The result is that some relationships are intense and short-lived.

Bipolar disorder doesn’t have these issues with relationships outside of the consequences of a mood episode. While they may damage relationships in mania, BPD is known for unstable relationships all of the time. They pull someone close and then push them away when it becomes uncomfortable.

This is truly what sets BPD apart from other mental health disorders.

Fragile Sense of Self-Image in BPD

Beyond an elevated mood or a depressive episode, borderline personality disorder is also marked by a very fragile sense of self. You may not have a firm grasp on who you are as a person. Instead, you will likely define yourself based on your relationships and proximity to other people.

Your self-image is constantly shifting because you have shifting goals and relationships. You might have close relationships one day and none the next, and this impacts who you feel that you are as a person. As a result, you likely don’t know who you are, what you want, or where you would like to be in the future.

Those with bipolar disorder have a stronger sense of self. They might not know who they are without the mood episodes, but they have a more cohesive sense of self with clear goals and motivations for their behavior.

Issues with Self-Harm and Suicidal Behaviors

Borderline and other personality disorders might also put you at an increased risk of suicidal behaviors and a tendency to self-harm. Oftentimes, this is born from intense feelings or the impulsivity that comes with the territory. These intense feelings are often unbearable and can lead you to try to self-soothe.

However, it can also stem from a desire to exert control over another person, forcing them to prove that they will come to your aid.

People with bipolar disorder are less likely to experience these behaviors unless they are experiencing depressive or mixed episodes. It isn’t aimed at forcing someone to respond the “right” way to your cry for help and is instead a direct result of a deep depression.

Difference in Origin of the Disorders

One of the other things that sets these two disorders apart and can lead to a proper diagnosis is their underlying causes. Bipolar is triggered by genetic predisposition. If someone else in your family history has the disorder, you are more likely to experience it as well.

People with borderline personality disorder are more likely to have experienced something traumatic in their childhood that leads them to have unstable relationships. They may have been the victims of sexual abuse, emotional neglect, and other forms of abuse.

As a result, someone with BPD has learned that others can’t be counted on to love them and be there for them when it matters. This triggers their mood shifts rather than the chemical or biological change that someone with bipolar disorder will experience.

Distinct Treatment Plan for Both Bipolar Disorder and BPD Clients

One of the main differences between bipolar and borderline personality disorder is that they respond to treatment very differently. What can you expect from the different treatments for each?

Bipolar disorder is typically treated with some combination of mood stabilizers under the care of a skilled psychiatrist. This is the best way to control the extreme highs and lows of the disorder. In addition, you may use talk therapy to learn how to navigate and cope with mood episodes when they do surface because medication isn’t a foolproof solution.

For those with severe issues arising from borderline personality symptoms, BPD residential programs here at Catalina can offer both structure and support.

On the other hand, the frontline treatment for borderline personality disorder is dialectical behavioral therapy. This teaches you to cope with uncomfortable feelings and chaotic relationships in a healthier way with DBT skills.

You may also have medication management for co-existing depression or anxiety, both of which are quite common in BPD.

Getting Help for Mental Health at Catalina Behavioral Health

Are you unsure whether your present issues are triggered by bipolar disorder or borderline personality disorder? The best thing you can do for yourself is to seek treatment for help with mental health, where you can be evaluated by a team of expert clinicians who can figure out the underlying reason for your discomfort and struggle.

Catalina Behavioral Health offers both residential and outpatient care for those struggling with mental health and substance abuse. We provide you with a comprehensive assessment and a customized treatment plan that will help you get to the bottom of things once and for all.

Our enrollment team is ready and waiting to answer your questions and help you get proper treatment. In a quick, confidential phone call, we can verify your insurance benefits and help you enroll in the right level of care.

Reach out to us today to learn more about our programs for your mental health!

References

1. Sanches M. (2019). The Limits between Bipolar Disorder and Borderline Personality Disorder: A Review of the Evidence. Diseases (Basel, Switzerland), 7(3), 49.
2. Mneimne, M., Fleeson, W., Arnold, E. M., & Furr, R. M. (2018). Differentiating the everyday emotion dynamics of borderline personality disorder from major depressive disorder and bipolar disorder. Personality disorders, 9(2), 192–196.
3. Eskander, N., Emamy, M., Saad-Omer, S. M., Khan, F., & Jahan, N. (2020). The Impact of Impulsivity and Emotional Dysregulation on Comorbid Bipolar Disorder and Borderline Personality Disorder. Cureus, 12(8), e9581.
4. Brady, K. T., & Sonne, S. C. (1995). The relationship between substance abuse and bipolar disorder. The Journal of clinical psychiatry, 56 Suppl 3, 19–24.
5. Trull, T. J., Freeman, L. K., Vebares, T. J., Choate, A. M., Helle, A. C., & Wycoff, A. M. (2018). Borderline personality disorder and substance use disorders: an updated review. Borderline personality disorder and emotion dysregulation, 5, 15.
6. Jain A, Mitra P. Bipolar Disorder. [Updated 2023 Feb 20]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from:
7. Chapman J, Jamil RT, Fleisher C, et al. Borderline Personality Disorder. [Updated 2024 Apr 20]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from:
8. Manji, H. K., Quiroz, J. A., Payne, J. L., Singh, J., Lopes, B. P., Viegas, J. S., & Zarate, C. A. (2003). The underlying neurobiology of bipolar disorder. World psychiatry : official journal of the World Psychiatric Association (WPA), 2(3), 136–146.
9. Herman, J. L., Perry, J. C., & van der Kolk, B. A. (1989). Childhood trauma in borderline personality disorder. The American journal of psychiatry, 146(4), 490–495.
10. May, J. M., Richardi, T. M., & Barth, K. S. (2016). Dialectical behavior therapy as treatment for borderline personality disorder. The mental health clinician, 6(2), 62–67.