Borderline personality disorder (BPD) and bipolar disorder are often confused for each other. While they’re two separate conditions, they do share some similarities.

Because of their similarities, some people receive a diagnosis of bipolar disorder when their symptoms better match BPD criteria, or vice versa.

The National Institute of Mental Health reports that, based on data from 2001 to 2003, around 2.8% of U.S. adults may live with bipolar disorder each year, and around 1.4% may live with BPD. Still, our data on BPD are imprecise because of the relatively high rate of misdiagnosis.

According to an older study, 40% of the people who met the diagnostic criteria for BPD, but not for bipolar disorder, were misdiagnosed with bipolar II disorder.

BPD and bipolar disorder both come with challenges, but you can live well and manage either condition. Getting the most accurate diagnosis can help you and your treatment team figure out what will work best for you.

Borderline personality disorder and bipolar disorder have a few symptoms in common with one another. These include:

  • changes in mood
  • impulsivity
  • fragile self-esteem or self-worth
  • self-destructive behaviors, such as substance use
  • suicidal thoughts or actions

To an outsider, BPD and bipolar disorder might look very similar. However, there are some key differences.

Symptoms of bipolar disorder

Bipolar disorder is characterized by extreme changes in mood. There are three main types — bipolar I disorder, bipolar II disorder, and cyclothymic disorder — each with different characteristics.

In bipolar disorder, you may have periods of extreme ups, known as mania or hypomania, or extreme downs, known as depressive episodes. Many people have both ups and downs.

The symptoms of mania and hypomania include:

  • higher activity and energy levels
  • a decreased need for sleep
  • inflated or grandiose self-esteem
  • engaging in harmful or self-destructive behaviors
  • making plans you’re unable to keep
  • thinking and talking faster than usual

While symptoms are similar between mania and hypomania, how long the mood episode lasts and the severity are where they differ.

During a period of depression, you might:

  • have a down, depressed mood (different from sadness)
  • lack interest or pleasure in enjoyable activities for at least 2 weeks
  • have less energy
  • struggle to concentrate, eat, or sleep
  • feel sad, hopeless, or irritable
  • have low self-esteem
  • self-harm
  • have suicidal thoughts or actions

Want to learn more? You can read about bipolar disorder symptoms here.

Symptoms of borderline personality disorder

The symptoms of BPD can include:

  • a frantic drive to avoid feeling abandoned, whether the abandonment is real or imagined
  • a pattern of high-conflict, intense relationships
  • an unstable self-image
  • impulsive behaviors, including possibly self-destructive ways
  • unstable emotions
  • mood lability, or rapidly shifting moods, (e.g., shifting from depressed to more content)
  • self-harm
  • suicidal thoughts or actions
  • outbursts of anger, even when it appears irrational
  • feelings of emptiness
  • paranoid thoughts

BPD symptoms vs. bipolar disorder symptoms

Although there’s some overlap between the two conditions, there are a few differences.

The main differences between BPD and bipolar disorder symptoms are:

The timing of impulsive behaviors

If you have bipolar disorder, your impulsivity tends to happen during periods of mania or hypomania. But if you have BPD, impulsive urges may arise without other symptoms of mania. Impulsive urges may arise anytime or may occur in response to stressors that happen randomly.

Sleep

During periods of mania, people with bipolar disorder feel more energized and need less sleep. You might feel energized after just a few hours of sleep each night. BPD doesn’t involve mania, so you’re less likely to notice this.

Mood cycle time

People with BPD have short-lived moods that change within a few hours or days. People with bipolar disorder tend to have mood cycles that last for weeks or months, unless they have rapid-cycling bipolar disorder, in which case the mood cycle will be much shorter.

Relationships

BPD is characterized by a deep fear of abandonment, which can put immense strain on relationships. People with BPD often struggle to have stable relationships as they fluctuate between extreme like and dislike for people. While people with bipolar disorder might struggle with interpersonal relationships, the fear of abandonment isn’t often present.

Triggers

People with BPD are intensely affected by the way others treat them, especially if they perceive someone to be abandoning them. A perceived abandonment can trigger an intense change in mood, leading to conflict, self-destructive behaviors, or self-harm. Triggers in bipolar disorder can sometimes occur due to stress, but can at other times occur for no identifiable reason.

Self-esteem

Inflated self-esteem or grandiosity can occur in bipolar disorder, which can sometimes even take the form of psychosis-like symptoms, such as delusions.

If you’re talking with a healthcare professional, they’ll often pay attention to the above areas to help you work out whether your symptoms fit the criteria for BPD or bipolar disorder (or neither).

Experts aren’t exactly sure what causes either bipolar disorder or BPD, but a number of factors could cause or contribute to the conditions. Some factors are common to both conditions.

Causes of bipolar disorder include:

  • genetics
  • trauma
  • substance use
  • changes in brain chemistry

Causes of BPD include:

  • genetics
  • trauma
  • abnormal brain structures
  • serotonin levels

Another potential cause of BPD involves harsh or critical parenting styles from a parent or caregiver while you’re developing.

As for trauma, it’s thought that trauma related to BPD likely occurs in childhood or early adolescence and is usually interpersonal in nature, such as assault.

Both conditions can be inherited. You’re more likely to develop these conditions if your sibling or parent has it. Still, most people who have relatives with either condition don’t develop it.

With the right treatments, people with BPD and bipolar disorder can learn to manage their symptoms, reduce distress, and improve their quality of life.

Psychotherapy is a common treatment for BPD and bipolar disorder. Also known as talk therapy, this involves talking with a therapist on a regular basis.

Psychotherapy can be used for bipolar disorder, but it’s most helpful if the individual is also taking mood stabilizing medications at the same time.

While cognitive behavioral therapy (CBT) is often used for treating bipolar disorder, dialectical behavioral therapy (DBT) is considered the most effective therapy for BPD.

In some cases, group therapy may be helpful, too.

A doctor or psychiatrist will usually prescribe medication for bipolar disorder. This could include:

  • mood stabilizers
  • antidepressants
  • antipsychotic medication

While there’s no specific meds developed for BPD, some people might benefit from the above medications.

For instance, depression can develop in someone with BPD, so antidepressants or other meds can help treat these symptoms.

In some cases people with either condition may need to visit the hospital for their symptoms, especially during times of severe stress or if they’re experiencing suicidal thoughts or intent.

BPD and bipolar disorder are often confused or misdiagnosed for one another. You may also be diagnosed with one of these conditions when you actually have an entirely different mental health condition.

Can you have both BPD and bipolar disorder? Yes, it’s possible — but it’s rare. This is called a dual diagnosis.

Other conditions that might be confused with bipolar disorder and BPD include:

Other possible diagnoses include antisocial personality disorder or narcissistic personality disorder. These conditions are diagnosed less often than BPD.

If you think your diagnosis may be incorrect, you can reach out to a mental health professional for a reevaluation. And it’s OK to get a second opinion.

It can help to look for a pro who specializes in treating BPD or bipolar disorder.

Bipolar disorder and BPD are both mental health conditions that affect your mood and behaviors, with some similarities in symptoms and causes.

While some treatments are similar, too, having a treatment plan tailored to your specific situation and needs can make a big difference in managing your symptoms.

If you believe you or someone you love has one of these conditions, a good starting place is reaching out to a healthcare professional. Talking with a professional is a helpful first step toward feeling better and improving quality of life.

For helpful resources, you can check out these websites:

Local in-person support groups, as well as online forums, might also help you and your loved ones.