Bipolar Disorder vs. Borderline Personality Disorder

Diagnosing mental health disorders is not quite as clear-cut as diagnosing a physical problem, such as diabetes or cancer. Many symptoms of mental illnesses overlap and can fluctuate from day to day, or week to week. Unfortunately, this means physicians frequently diagnose patients incorrectly, prolonging the start of appropriate and effective treatment. This problem often occurs with two common mental health conditions: bipolar disorder and borderline personality disorder.

Bipolar Disorder

People with bipolar disorder have fluctuations in mood, energy, and activity that vary along a continuum anchored at each end by depression and mania (hyperactivity, euphoria). The periodic episodes of mania distinguish bipolar disorder from general depression. Bipolar disorder is the sixth leading cause of disability between ages 15 and 44. It often coexists with other mental health disorders, such as substance abuse, panic disorder, and Obsessive Compulsive Disorder (OCD). In between mood episodes, those who suffer from bipolar disorder are capable of functioning at a relatively normal level.

Borderline Personality Disorder

Borderline personality disorder (BPD) is primarily an inability to regulate emotions. Sufferers experience pervasive mood instability, excessive or impulsive behavior, and unstable relationships. Borderline personality disorder accounts for 20 percent of psychiatric hospitalizations, and individuals with BPD are at higher risk for suicide. Many BPD sufferers have a history of abuse, neglect, and separation.

What are the Differences?

Eighty-five percent of those with BPD also meet the criteria for other mental health disorders, including bipolar disorder. However, there are a few important differences.

  • People with BPD do not experience periods of mania, which are the hallmark of bipolar disorder.
  • Bipolar mood swings alternate between depression and mania with periods of relative stability in between. Mood episodes can last for days or weeks. In contrast, people with BPD exhibit short, intense bouts of anger and anxiety.
  • Individuals with BPD suffer from pervasive feelings of chronic emptiness, abandonment, and fear. They tend to feel they are bad or unworthy, and often complain they are unfairly misunderstood or treated.

Treatment Options

The first line of treatment for people with bipolar disorder is medication, which physicians may augment with psychotherapy. In contrast, psychotherapy is the primary treatment for borderline personality disorder. Dialectical Behavior Therapy, a type of psychotherapy that's specific to borderline personality disorder, is generally effective.

It's important to recognize these differences. In a 2008 study, one in four mental health patients were not initially diagnosed correctly. These misdiagnoses lead to higher rates of psychiatric hospitalization and medical costs.


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