The Difference Between Borderline and Bipolar Disorders

What is the difference between borderline and bipolar disorders? People may confuse borderline and bipolar disorder due to them having two or three similar symptoms. However, they are very different, each with unique characteristics that help professionals diagnose and treat them appropriately. Borderline, a personality disorder, and bipolar, a mood disorder, can have a severe impact on someone’s life and interfere with daily functioning if left untreated.

Borderline personality disorder (BPD) and bipolar disorder (BD) are two of the more common mental illnesses. One of the signature traits of BPD is a person’s inability to regulate their emotions. With BD, a person’s mood changes in cycles from depression to mania.

Getting the correct diagnosis is crucial to avoid the adverse effects of both disorders.

This article explores the difference between borderline and bipolar.

What is Borderline Personality Disorder?

The National Alliance on Mental Illness reports that 1.4% of Americans have BPD, with 75% being women. Someone with BPD may experience a trigger event that leads to intense emotional dysregulation. Examples of trigger events include relationship breakups, arguments, or rejections, which can lead to engaging in unhealthy or harmful behaviors. The trigger event can be real or imaginary.

What is Bipolar Disorder?

BD is a mood disorder in which a person may experience cycling between extreme highs and lows or depression and mania. The National Institute of Mental Health estimates 2.4% of American adults have bipolar. Adults between 18 and 29 have the highest rates of BD. The effects of bipolar go beyond ordinary ups and downs and cause significant impairment in how a person functions.

The Difference Between Borderline and Bipolar Disorders

Many symptoms make it easier to distinguish between borderline and bipolar disorders. Areas of difference include mood stability, triggers, symptoms, impact on self, and treatment options. Each disorder requires that someone meets the diagnostic criteria the American Psychiatric Association sets.

So, what is the difference between borderline and bipolar disorders?

Mood Stability: Rapid Swings vs. Long Episodes

Borderline and bipolar disorders involve mood instability, but they differ in how mood swings occur. Someone with borderline personality disorder experiences rapid mood swings. They can go from happy to angry shortly after a triggering event. They can also return to feeling calm rather quickly and may also feel guilt or shame regarding their emotional changes.

Bipolar disorder, on the other hand, consists of mood swings that last for longer. They may experience days, weeks, or months of extreme depression before their mood shifts to long periods of mania.

The intensity of mood swings and how long the episodes last will vary from person to person.

Triggers: Interpersonal Stress vs. Biochemical Changes

With borderline personality disorder, triggering events lead to immediate, intense reactions and interpersonal stress. Someone may feel another person is betraying or slighting them, causing an emotional outburst. Whether the triggering event is real or imaginary does not matter.

Bipolar disorder mood swings are random, but some triggers may cause the shift, like getting very little sleep or misusing drugs or alcohol. Another trigger for BD mood swings is the biochemical changes that take place in the brain. When out of balance, mood changes drastically. Too many chemicals may lead to mania, while too few chemicals may lead to depression.

Symptom Duration: Short-term vs. Long-term

BPD symptoms may occur randomly, on any day, and at any time. Therefore, coping with symptoms is a daily challenge. Initial symptoms start to appear in young adulthood and, for some, fade with age. Some people may have frequent daily mood swings, and others may go days in between mood swings.

Bipolar disorder symptoms of mania last at least two weeks and may take additional weeks or months before a person begins to experience a change in mood. Depressive episodes may also last for two or more weeks. BD typically begins in teens and young adults between 15 and 19. Adults can develop it also, but the chances diminish with age.

Relationship Impact: Intense in BPD, Varied in Bipolar

When a partner has BPD, it can make the relationship feel like it is on a roller coaster of ups and downs. One moment, they are loving and doting, and when triggered by a feeling of abandonment, they immediately become desperate to fix the relationship. They fear rejection but use the wrong tactics to save the relationship.

Bipolar disorder can affect relationships in various ways, including intimacy. During manic phases, a person with BD may experience an increase in sex drive. During depressive phases, they may avoid intimacy altogether. The partner of a person with BD can expect to take on more responsibilities regarding parenting, finances, and household chores since symptoms can significantly impact their functioning.

Self-Image: Unstable in BPD, Steadier in Bipolar

Unstable self-image and self-worth are key symptoms of BPD. They tend to have an identity disturbance in which they adapt their personality to match their current situation. For example, they may constantly change their career, dreams, goals, and beliefs to fit specific situations or relationships.

Self-image can vary with episodes, like feeling unworthy and isolated during depressive episodes and overconfident and grandiosity and extreme confidence during manic episodes. Self-image is based on how one compares to others socially or professionally. Their moods determine their feelings about themselves, which may seem steadier because episodes last much longer than in BPD.

Treatment Approaches: Psychotherapy for BPD, Medication Plus Therapy for Bipolar

BPD treatment includes psychotherapy to teach someone skills for managing emotions. Behavioral therapies include cognitive-behavioral therapy (CBT), dialectical-behavioral therapy (DBT), schema therapy (ST), and transference-focused therapy (TFT). BPD therapies may also include psychoeducation and family therapies.

Someone with bipolar may benefit from medications, including antidepressants and antipsychotics. Doctors often combine medications with therapies such as the ones listed for bipolar disorder plus interpersonal and social rhythm therapy (IPSRT).

Diagnosis Distinctions: Personality vs. Mood Disorder

A diagnosis of borderline personality disorder involves showing problems with impulsivity in five of the following ways:

  • Avoiding abandonment
  • Unstable relationships
  • Unstable sense of self or self-image
  • Impulsivity
  • Suicidal or self-harming behaviors
  • Unstable affect
  • Consistently feeling empty.
  • Intense anger

A diagnosis of bipolar disorder requires a person to experience mania and hypomania for at least one week and present for each day, most of the days. Mania symptoms must also be present, such as:

  • Inflated self-esteem
  • Lack of sleep
  • Impulsive behaviors
  • Increased thoughts and speech
  • Depressive symptoms may include:
  • Loss of interest in activities
  • Over-sleeping
  • Low self-worth
  • Self-harm thoughts or actions

Explore Mental Health Treatment at the Mental Health Center

Are you experiencing the symptoms of borderline personality or bipolar disorder? Do you need help determining if you have one or the other? Are you interested in learning about the treatment options for each disorder? The Mental Health Center at Cedars Sinai Medical Center is here to help.

The Mental Health Center can connect you with psychiatrists and psychologists in Los Angeles who can create and provide an individualized treatment plan. If you’re in Los Angeles and ready to explore treatment, the Mental Health Center can help guide you.

Contact the Mental Health Center to schedule an appointment with a provider today.


The difference between borderline and bipolar disorders vary in many ways, including symptoms, diagnostic criteria, and treatment options. Following a comprehensive assessment, you can get a diagnosis and a unique treatment plan to meet your needs. Call us today to get started.