Borderline Personality (BPD) vs. Bipolar Disorder (BD)

Borderline personality disorder (BPD) and bipolar disorder (BD) are mental illnesses associated with dramatic mood swings. They share common features and are often confused with one another.

The main difference between bipolar disorder and BPD is that bipolar is a mood disorder, and BPD is a personality disorder.

Bipolar, previously known as manic-depressive disorder, features extreme highs and lows that can last for weeks or months. With BPD, however, moods fluctuate more rapidly, cycling through emotional states in a matter of hours or days.

The differences in BPD vs. bipolar symptoms can help steer a diagnosis. The two are also treated differently, so it's crucial to get an accurate diagnosis.

This article discusses the differences and similarities between BPD and bipolar disorder. It also details the different causes and treatments of the two mental health conditions.

Symptoms of BPD vs. Bipolar

BPD and bipolar share some of the same traits, but they have different symptom patterns, durations, and triggers.

Some symptoms are also more common with one versus the other. For example, both BPD and bipolar are characterized by emotional turbulence and impulsive behavior. But people with BPD often have unstable personal relationships, which is not as common in bipolar disorder.

BPD Symptoms

The main symptoms of BPD include:

• Dramatic emotional changes lasting from a few hours to a few days
• Impulsive, risky, and unsafe behavior
• Inappropriate anger
• Feelings of emptiness and low self-worth 
• Self-injury or thoughts of self-harm
• Chronic depression
• Distorted self-image
• Fear of abandonment
• Unstable and intense relationships

People with BPD may also show signs of uncontrolled aggression. The impulsive nature of BPD can make a person more likely to engage in addictive behavior, like drug use and gambling.

Moreover, the symptoms are usually triggered by a conflict with another person or institution. A traumatic or stressful event can also cause an increase in BPD symptoms.

Another feature of BPD is called splitting. This term, which refers to two things being split in half, occurs when someone is unable to hold emotionally opposing viewpoints in relation to themselves and others.

As a result, people with BPD tend to view the nature of people and situations as either black-or-white, good-or-bad, or all-or-nothing. With splitting, everything is either the best or the worst—there is no middle ground.

Splitting is usually a coping or defense mechanism to manage the intense fear of abandonment, and it can result in impulsive behaviors and relationship difficulties.

Bipolar Disorder Symptoms

The main symptoms of bipolar include dramatic changes in mood states.

The highs, or elevated, expansive, or irritable periods, are considered manic episodes. The lows, or sad, empty, or hopeless periods, are depressive episodes.

Experiencing both manic episodes and depressive episodes differentiates BD from major depressive disorder (MDD), which is dominated by only depressive episodes.

During manic episodes, symptoms of bipolar include:

• Decreased need for sleep
• Inflated self-esteem or grandiosity
• Elevated mood, euphoria, and irritability
• Excessively talkative
• Racing thoughts
• Impaired judgment
• Easy distraction
• Threatening and assaultive behavior

During depressive episodes, symptoms of bipolar include: 

• Depressed mood
• Flat or limited expression
• Feelings of guilt and failure
• Impairment in cognition and memory
• Soft, slow speech
• Lack of energy and motivation
• Overemphasis on negative feelings and beliefs
• Weight changes
• Insomnia
• Recurrent thoughts of death or suicide

It’s also important to understand manic episodes in bipolar aren’t necessarily beneficial, even though they’re the alternative to depressive episodes. People experiencing mania can be reckless. They often lack self-awareness and are unable to understand how their impulses affect themselves and others.

People with bipolar I disorder often have cycles that switch from a depressive state to a manic state. Manic symptoms sometimes include symptoms of depression within the manic episode, which is called mixed features.

Do BPD and Bipolar Have Different Causes?

There are a number of complex factors that can cause BPD or bipolar.

Many of the experiences with emotional dysregulation in BPD are in response to relationship interactions, while bipolar symptoms can be triggered by a wide variety of factors, including chemical imbalances in the brain and stressful life events.

Borderline Personality Disorder Causes

The exact cause of BPD is not entirely known, but research suggests that it can be influenced by environmental factors, especially those in early childhood.

A history of emotional, physical, or sexual abuse or parental neglect is prevalent in people with BPD. Parental substance abuse is another potential cause. Research has shown that experiencing stress and trauma as a child and an inability to cope can contribute to BPD later in life.

Genetics, chemical imbalances, and brain structure may also play a role in BPD. People with a family history of BPD are at higher risk of having the condition. Many people with BPD have altered brain neurotransmitter function, particularly serotonin.

Studies have shown that people with BPD can have structural and functional changes in the brain, especially in the areas that control impulses and emotional regulation like the amygdala, hippocampus, and orbitofrontal cortex.

Bipolar Disorder Causes

The causes of bipolar disorder are complex. Most agree that there is no single cause, and a combination of factors often contributes to BD. People who have a direct relative with BD are more likely to develop it. Some research also suggests that people with certain genes are more likely to develop bipolar. 

Researchers believe that chemical imbalances play a role in bipolar. There is evidence that an imbalance in one or more neurotransmitters may result in bipolar symptoms.

BPD vs. Bipolar Triggers

Another difference between BPD and bipolar disorder is their triggers. A wide range of factors can trigger bipolar episodes, while BPD episodes are typically related to relationship issues.

BPD Triggers

Triggers for BPD mood swings include:

• Criticism
• Fear of abandonment
• Fights with friends or loved ones
• Job loss
• Rejection
• Romantic problems
• Traumatic memories
  

Bipolar Triggers

Bipolar episodes can be triggered by:  

• Hormonal changes
• Low thyroid hormone levels
• Negative life events
• Nutritional deficiencies, including vitamins B12 and D
• Poor sleep 
• Seasonal changes
• Stress
• Substance use
• Weather changes
  

Different Diagnostic Criteria for BPD and Bipolar

Bipolar disorder and BPD can be diagnosed by a psychologist, psychiatrist, or other mental health professionals. They have different diagnostic criteria, as outlined in the Diagnostic and Statistical Manual 5^th Edition (DSM-5).

Bipolar is diagnosed when a person experiences a manic episode that is preceded or followed by a depressive episode. It has two forms:

• Bipolar I features more intense manic episodes.
• Bipolar II has less intense hypomanic episodes.

BPD is diagnosed when a person has a pattern of unstable relationships, impulsivity, and struggles with their sense of self. 

Other subtle diagnostic distinctions between BPD and bipolar disorder include:

• Duration: A manic or depressive episode of bipolar can last weeks, months, or longer. In contrast, people with BPD have shorter episodes of mood instability that are reactive to stress.
• Family history: Genetic factors can also help differentiate the two. Mood disorders, like bipolar, are more likely to be passed down through family members than borderline personality disorder.
• Sleep: Sleep changes are often an early indicator of bipolar disorder. In bipolar disorder, during a manic episode, a person might be awake for days without experiencing fatigue. Meanwhile, sleep patterns are less commonly affected in BPD.
• Relationships: People with BPD have more distinct challenges interacting with others, so they often have a history of turbulent personal relationships or may lack close and trusted friends.
• Self-harm: Self-harm behaviors such as cutting are more common in BPD.

While both BPD and bipolar can vary in severity, BPD symptoms tend to be more pervasive, last longer, and cause more serious disability. While bipolar disorder can also be debilitating, it is more responsive to treatment and, therefore, more manageable.

How Common Is Misdiagnosis?

Since the two have similar and overlapping diagnostic criteria, misdiagnosis is common. One study estimates up to 40% of those with BPD were first misdiagnosed with bipolar.

People can also be misdiagnosed with BPD instead of bipolar. In some cases, BPD is misdiagnosed in people who actually have autism. This is more common in females and people with a higher IQ whose autism goes undetected in childhood.

Treatment

The most effective treatment for these conditions is a personalized treatment plan that suits the symptoms, personal needs, and lifestyle.

BPD

Psychotherapy is the first-line treatment for people with BPD.

There are several types of empirically supported psychotherapies used in BPD, including:

• Dialectical behavioral therapy (DBT), which supports emotional management
• Mentalization-based therapy (MBT), which promotes a better understanding of what happens in your mind

The benefits of medications for BPD are less clear. In some cases, a psychiatrist may recommend medications to treat specific symptoms, such as mood swings, depression, and other co-occurring mental disorders.

Lifestyle adjustments that promote a balanced mood and practicing self-care habits, like getting regular sleep and exercise, and participating in psychoeducation, can help keep the condition under control.  

Bipolar Disorder 

Having bipolar disorder increases a person’s risk of mortality and shortens their life expectancy.

This is partly due to increased rates of suicide—an estimated 20% of those with bipolar disorder take their own life. However, the majority of people with bipolar disorder die of natural causes. Research links a decreased life expectancy to poor management of underlying health conditions.

Fortunately, treating bipolar disorder can improve a person's ability to care for their health.

Doctors can treat BD with medications and psychotherapy. Typically, psychiatrists prescribe mood stabilizers and second-generation antipsychotics for the treatment of bipolar They may also prescribe antidepressant medication to treat depressive episodes in BD.

Psychotherapies that can be used for the treatment of bipolar disorder include cognitive-behavioral therapy and psychoeducation. Other therapies designed specifically for the treatment of BD include interpersonal and social rhythm therapy and family-focused therapy.

Sometimes bipolar is treated with electroconvulsive therapy, a brain stimulation procedure used to treat severe or refractory manic and depressive episodes. Transcranial magnetic stimulation is also used, which stimulates the brain with magnetic waves to help treat subtypes of depression.

A Word From Verywell

Bipolar disorder and BPD are not the same. Having bipolar or BPD can have a significant impact on your life. However, proper maintenance of symptoms can reduce the risk of potential consequences, including substance abuse, suicidal thoughts, and self-harm.

If you or a loved one may be struggling with a mental health challenge like BD or BPD, talk to your doctor about options for evaluation and treatment.