Borderline personality disorder (BPD) and bipolar disorder might seem pretty similar. They both can cause intense mood fluctuations, influence self-image, and cause impulsivity. But if we dig deeper, we’ll see how different they are. Read the article to discover what people with bipolar disorder and borderline personality disorder experience, compare their symptoms, and find out more about treatment.
What is borderline personality disorder (BPD)?
Borderline personality disorder is a mental health condition that is characterized by unstable self-image, impulsive actions, fear of abandonment, and unstable relationships. BPD may involve a lack of self-confidence and trouble managing thoughts that may lead to reckless behavior.
DSM-5-TR diagnostic criteria for BPD:
- A strong fear of abandonment.
- Very unstable relationships.
- Unstable sense of self.
- Taking risks without thinking about what might happen.
- Thoughts of suicide keep coming back.
- Extreme shifts in mood.
- Constant feelings of emptiness.
- Strong or uncontrollable anger.
- Feeling paranoid or disconnected when you’re under a lot of stress.
Statistics provided by the National Alliance on Mental Illness show that around 1.4% of the adult US population experiences BPD. Yet, the real percentage can be higher, as some may confuse this mental illness with other conditions.
What is bipolar disorder?
Bipolar disorder is a mental health disorder that can cause intense mood shifts as well. It can include emotional highs, also known as mania or hypomania, and lows, also known as depression. Experiencing both mania and depression at the same time is also possible, which is called a mixed episode.
DSM-5 diagnostic criteria of manic episodes:
- Feeling overly confident.
- Not needing to sleep as much as usual and not feeling tired.
- Feeling like you can’t stop talking.
- Racing thoughts.
- Getting sidetracked easily.
- Being unusually active or feeling restless.
- Engaging in risky activities such as excessive spending, unprotected sex, or making poor business decisions.
The symptoms of depressive episodes:
- Low mood episodes.
- Losing interest in things you used to enjoy.
- Weight changes or changes in appetite.
- Trouble sleeping or sleeping too much.
- Moving much more slowly than usual.
- Feeling tired.
- Feeling worthless.
- Trouble focusing or making decisions.
- Thinking a lot about death or having suicidal thoughts (even without a clear plan).
Three primary classifications of bipolar disorder
Scientists identify 3 types of bipolar disorder that share common symptoms but differ in how intense the mood fluctuations are and how long they last.
- Bipolar I disorder includes at least one mania episode, which can be so intense that it might lead to losing touch with reality. You may also have had depression episodes or milder highs before or after.
- Bipolar II disorder. You’ve had at least one depression episode and one mild high (hypomania), but never a manic episode.
- Cyclothymic disorder. You’ve had lots of ups and downs for at least two years (or one year for kids/teens), but the highs and lows aren’t as strong as full mania or depression.
Key differences between BPD and bipolar disorder
Despite their initial similarities, these two mental health disorders exhibit significant differences in their symptoms, causes, and treatment plans.
| Aspect | Borderline personality disorder (BPD) | Bipolar disorder |
| Mood patterns | Tend to be rapid and intense mood changes that can shift within minutes or hours. | Can change from the elevated mood to depressive episodes that last for days or weeks. |
| Type of mood instability | Emotional instability, depressive symptoms, or intense anxiety | Highs (mania/hypomania) and lows (depression) |
| Sense of identity | Unstable self-image | Between episodes, identity might be stable |
| Impulsivity | May be frequent | Might happen during severe manic episodes |
| Self-harmful behavior | Common and may be triggered by emotional pain or fear of rejection | Can happen during depressive episodes |
| Treatment | Dialectical behavior therapy (DBT), cognitive behavioral therapy (CBT), and mentalization-based treatment (MBT). | Medications (mood stabilizers, antidepressants), electroconvulsive therapy (ECT), and talk therapy. |
Symptoms comparison of bipolar disorder and borderline personality disorder
Borderline personality disorder and bipolar disorder can lead to intense mood swings and extreme impulsivity. However, there are some differences between these mental disorders.
1. Mood changes
- Borderline personality disorder involves quick and short-lived mood changes that come from stressful events, interpersonal conflicts, or fear of abandonment.
- People with bipolar disorder tend to experience mood swings that can last for weeks. Typically, these changes aren’t tied to specific events and triggers but rather to inner reasons.
2. Impulsivity
- Those with borderline personality disorder may exhibit impulsive behavior because of excessive emotional pain and inner worries. Impulsive actions can be quite reactive and unpredictable.
- Bipolar disorder can also cause extreme mood swings and troubles with emotional control. People tend to behave impulsively during manic phases. Moreover, their actions can be driven by elevated energy or unrealistic confidence rather than emotional distress.
3. Interpersonal relationships
- Those living with borderline personality disorder may experience intense relationships with others, which might be rather unstable. As a core symptom of BPD is the fear of abandonment, such people may live with insecure attachment styles and idealize others.
- Relationships of people with bipolar disorder may be different based on the episode they’re experiencing. During manic phases, they may have chaotic relationships, while during depression, people may find it difficult to maintain emotional closeness.
4. Managing emotions
- Reactivity and problems with emotional regulation are quite common for BPD, according to the study published in the Harvard Review of Psychiatry. A person may experience intense anger outbursts, sudden mood shifts, or overwhelming sadness.
- While intense emotions may be typical, those with bipolar disorder don’t tend to show up as emotionally reactive in everyday situations. Over manic phases, there can be heightened irritability or exaggerated emotional responses — but they are usually tied to the episode, not everyday interactions.
Causes and risk factors of bipolar disorder and BPD
While studies are still being conducted, these separate conditions seem to have some similar causes. However, they differ in how these factors interact and show up in symptoms.
Borderline personality disorder
1. Childhood experiences and trauma
Studies prove that in 30% to 90% of cases, BPD is associated with emotional neglect and childhood abuse (emotional, physical, or sexual abuse). [1] When caregivers don’t accept the child’s emotions, the child may struggle to manage their feelings and start swinging between emotional outbursts and shutdowns.
These early wounds can shape how the child sees themselves and others and lead to an unstable self-image. The child may also develop coping strategies, such as impulsive behavior or emotional withdrawal, which are also symptoms of BPD.
2. Genetic factors
The National Alliance of Mental Illnesses states that there’s no specific gene or gene profile that directly causes BPD. Yet, genetic factors account for 40-60% of BPD variation. [2] So, people who have a close family member with borderline personality disorder may be at a higher risk of developing this mental health condition.
3. Differences in brain structure
People with borderline personality disorder can show changes in how their brain handles emotions. Their amygdala (the part of the brain linked to emotional reactions) can be overly active, while another part of the brain, called the anterior cingulate cortex (ACC), which helps control emotions, may function differently. This pattern is similar to what we can see in animals under long-term stress or depression. [3]
4. Hyperbolic temperament
Zanarini and Frankenburg suggested that BPD may develop when a person has a very intense, sensitive temperament. When something stressful happens in their environment, it can “set off” or trigger strong symptoms. This emotional sensitivity, combined with negative life experiences, might contribute to the development of BPD symptoms.
Bipolar mood disorder
1. Genetic factors
According to the research published in Dialogues in Clinical Neuroscience, bipolar disorder, especially type I, has a strong genetic component. Another study reveals that genetics accounts for around 60-80% of the risk of developing the disorder. [4]
2. Brain function
Neurons in the prefrontal cortex and hippocampus might also play significant roles in bipolar disorder development, according to the same study.
How often do you experience intense mood fluctuations?
Diagnosis: differences between bipolar and BPD
Diagnosing BPD involves observing a person’s behavior to understand how they function in the long run. Diagnostic criteria include persistent instability in relationships, self-image, and emotions.
Only a licensed mental health professional can diagnose BPD. Additional assessments might include:
- Interview with your doctor
- Completing a series of questions
- A discussion of your symptoms
A psychiatrist or another mental health provider typically diagnoses bipolar disorder. They may need to access your energy level, family history, and mood patterns. The evaluation might also include:
- Lab tests to rule out medical causes
- A mental health assessment with a psychiatrist to discuss thoughts and behaviors
- Mood charting to track mood and sleep changes
You can notice specific symptoms and significant mood changes by using Breeze. An advanced mood tracker allows you to track what triggers your emotions and how they change over time. Thus, if you experience any kind of mental condition, it will help you recognize its early signs.
Can you have both BPD and bipolar disorder?
Yes, co-occurring disorders are possible. Statistics from the research of Mark Zimmerman and Theresa A. Morgan state that:
- Approximately 10% of patients with BPD had bipolar I disorder, and another 10% had bipolar II disorder.
- About 20% of bipolar II patients and 10% of bipolar I patients were diagnosed with BPD.
This overlap can make diagnosis and treatment more challenging, as some symptoms can appear in both conditions.
Bipolar and borderline personality disorders & co-occurring mental illnesses
Both these mood disorders can also co-occur with other conditions, which complicates treatment. For BPD, these are:
- post-traumatic stress disorder (PTSD)
- eating disorders
- attention-deficit/hyperactivity disorder (ADHD)
For bipolar disorder, common overlapping disorders are:
- substance abuse
- anxiety disorders
Expert Insight
“Mental health specialists can determine whether or not these conditions co-occur with other mental health disorders with a comprehensive diagnostic assessment. They will consider which disorders frequently co-occur with borderline personality disorder and bipolar disorder. The most common comorbidities include substance abuse disorders, PTSD, and anxiety disorders.
They may perform clinical interviews. These look at the history of symptoms and how they affect psychosocial functioning. They may also use other assessment tools.”
Emily Mendez
Mental health professional
Treatment approaches for borderline and BPD: how they differ
Once a healthcare provider knows the proper diagnosis, they can choose how to manage symptoms. Let’s briefly introduce the primary treatment approaches.
How to treat people with borderline personality disorder
- Dialectical behavior therapy (DBT) is a type of cognitive behavioral therapy adapted for people who experience intense mood shifts. DBT helps people understand and accept their lives and actions while also showing them how to change behaviors that aren’t helpful.
- Cognitive behavioral therapy (CBT) is particularly used to treat many personality disorders, like major depressive disorder, anxiety, PTSD, or eating disorders. It’s considered highly effective because CBT uses different techniques to help people change their thinking, teach new skills, provide education, gradually face fears, and overcome them.
- Mentalization-based treatment (MBT) helps people better understand what’s going on in their own minds and in the minds of others. Patients with BPD show reduced capacities to mentalize, which leads to difficulties in managing impulsivity. [5] MBT teaches people to slow down, reflect, and respond more thoughtfully.
How to treat bipolar disorder
- Mood stabilizers. It’s common to use medications for bipolar disorder treatment. Mood stabilizers help control highs and lows that come with the condition. Yet, it’s essential to remember that different treatments or medications should only be prescribed by a mental health professional.
- Electroconvulsive therapy. A 2017 study has proven that ECT is an effective and safe treatment for severe and drug-resistant bipolar disorder. [6] During ECT, small electric currents are passed through the brain while you’re asleep under anesthesia. This helps reset brain activity and can improve symptoms of the disorder.
Why accurate diagnosis matters for mental health
Emily Mendez, M.S., Ed.S., states, “If a patient with bipolar disorder receives an incorrect diagnosis of borderline personality disorder, they will likely not receive the best treatment for this condition. That is because bipolar disorder is primarily treated with medications, while BPD is treated primarily with therapy. The person may continue to experience dangerous mood swings that are common in bipolar disorder. If a person with borderline personality disorder receives a diagnosis of bipolar, they may be treated primarily with medications, which is not the first-line way of treating borderline personality disorder. The symptoms of BPD may not improve much.”
Conclusion
Now, you’re more prepared not to confuse BPD and bipolar disorder and know how to treat both of them. Try Breeze’s mood tracker to understand why you might feel angry, anxious, or overwhelmed. Also, the Breeze app can help you set up a nurturing routine and build new habits to cultivate resilience, no matter what happens around you.
Sources
- Bozzatello P, Rocca P, Baldassarri L, Bosia M, Bellino S. “The Role of Trauma in Early Onset Borderline Personality Disorder: A Biopsychosocial Perspective.” Front Psychiatry. 2021
- Ansari D, Lakkimsetti M, Olaleye KT, Bhullar JVK, Shah RZ, Arisoyin AE, Nadeem H, Sacal Slovik SC, Habib FZ, Abdin ZU, Zia Ul Haq M. “Genetic Influences on Outcomes of Psychotherapy in Borderline Personality Disorder: A Narrative Review of Implications for Personalized Treatment.” Cureus. 2023
- Minzenberg MJ, Fan J, New AS, Tang CY, Siever LJ. “Frontolimbic structural changes in borderline personality disorder.” J Psychiatr Res. 2008
- Nature. “Genomics yields biological and phenotypic insights into bipolar disorder.” 2025
- Bateman A, Fonagy P. “Mentalization based treatment for borderline personality disorder.” World Psychiatry. 2010
- Perugi G, Medda P, Toni C, Mariani MG, Socci C, Mauri M. “The Role of Electroconvulsive Therapy (ECT) in Bipolar Disorder: Effectiveness in 522 Patients with Bipolar Depression, Mixed-state, Mania and Catatonic Features.” 2017
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