Difference between Bipolar Disorder and Borderline Personality Disorder

Two devastating disorders that affect some people are bipolar disorder and borderline personality disorder. This article will help explain the difference between the two.


Bipolar disorder, also known as manic depression, is a mental disorder characterized by periods of severe depression, known as depressive episodes, and elevated happiness levels, known as manic episodes.

Sufferers of bipolar disorder will feel depressed, angry, negative, and perhaps suicidal during depressive episodes. During manic episodes, however, they will feel abnormally happy and energetic, are sometimes prone to impulsive decision making and racing thoughts and speech. There are two subcategories of bipolar disorder, bipolar I and bipolar II, distinguished based on severity. Sufferers of bipolar I have not had full manic episodes and only a few hypomanic episodes. Sufferers of bipolar II, however, have had more severe manic episodes and more severe depressive episodes. Bipolar disorder can be treated with a combination of therapy and medication like mood stabilizers and antipsychotics. It is unclear how bipolar disorder originates, though childhood abuse, high stress levels, and certain genetic factors have been known to contribute.

Borderline personality disorder (BPD) is a cluster-B personality disorder. Cluster-B personality disorders are known as the erratic, dramatic, or emotional personality disorders, a category that also includes narcissistic personality disorder, antisocial personality disorder, and histrionic personality disorder. BPD was once called emotionally unstable personality disorder, and is defined by emotional instability, a shaky sense of self, instability in personal relationships, and impulsivity. Sufferers of BPD, known as borderlines, exhibit the following symptoms:

  • Black-and-white thinking, known as splitting (often manifesting in thinking of people as “all good” or “all bad”)
  • A strong fear of abandonment, usually stemming from an abusive childhood
  • Self-harm and suicidal ideation
  • Anxiety, depression, and rage
  • Strong intensity of emotions, but shallow emotions
  • Impulsivity
  • Instability in personal relationships

Borderlines often feel emotions very strongly, and have frequent mood swings. Borderlines are prone to feelings of victimization, and often engage in impulsive behavior (binge eating, promiscuity, reckless driving or spending). Borderline personality disorder can be treated and mitigated through dialectical behavior therapy (DBT), though many borderlines will never enter therapy because they are unlikely to blame themselves for what happens in their life.

Comparison chart

Bipolar Disorder Borderline Personality Disorder
Mental disorder Cluster B mental disorder
Can be treated with medication Cannot be treated with medication
Cycles occur less frequently Cycles occur more frequently
Cycles are less related to life events Cycles are more related to life events
Mood swings are more all-encompassing Mood swings are more specific

Bipolar Disorder vs Borderline Personality Disorder

What is the difference between Bipolar Disorder and Borderline Personality Disorder? The two disorders are very similar to one another, such that BPD is sometimes diagnosed as bipolar disorder, and vice versa. According to Psychology Today, there are three ways to differentiate bipolar disorder from borderline disorder.

Both borderline and bipolar disorders are defined in part by cycles. Borderlines and bipolar people go from periods of high elation and positivity to periods of deep depression and negativity. In bipolar disorder, these are known respectively as manic episodes and depressive episodes, while in borderline personality disorder, these episodes are more commonly referred to by the phrase “black and white thinking” or “splitting.”

However, borderlines change cycle much more frequently than bipolar people do. People suffering from borderline personality disorder will sometimes change cycle multiple times in a day, whereas this change of cycles is less frequent in bipolar disorder.

Moreover, when borderlines change cycle, it is often a direct result of things that are occurring in the borderline’s life that trigger a cycle. Cycle changes in bipolar people, on the contrary, are not as directly correlated with life events.

Typically, the mood swings in bipolar disorder go from all-encompassing periods of depression to all-encompassing periods of mania. In borderlines, the mood swings are more specific, with specific emotions like fear becoming more or less intense, or anxiety becoming more or less intense.
Bipolar disorder can be treated with mood stabilizers and antipsychotics. Borderline personality disorder, however, does not have a specific medication to cure the disorder. The nature of personality disorders is that they are usually malignant and toxic patterns of thinking and functioning rather than chemical imbalances in the brain. They may be better helped by psychotherapy.


The video below, from the Mayo Clinic, describes some differences between bipolar and borderline disorders.