What are the Differences Between Borderline Personality Disorder and Bipolar Disorder?

Jake Newby

| 4 min read

Borderline personality disorder (BPD) and bipolar disorder are both relatively common mental illnesses that can seriously affect a person’s emotions. These disorders share similar symptoms and risk factors and are both associated with mood swings, so they are often confused. But they are separated by a few distinct differences.

What is bipolar disorder?

Bipolar disorder is also known as manic depression. It is characterized by depressive and manic mood swings that are typically easy for others to notice. Individuals with bipolar disorder can swing from feeling joyful and energetic (manic episodes) to sad and helpless (depressive episodes). 
During periods of mania, a person might:
  • Become easily agitated or irritated 
  • Become delusional, experience hallucinations and have illogical thoughts
  • Become more impulsive 
  • Become more talkative and talk very quickly 
  • Experience bursts of creativity
  • Feel happy, elated and joyful 
  • Feel full of energy 
  • Show poor judgment 
  • Sleep less but does not feel tired
During periods of depression, a person might:
  • Become restless and irritable 
  • Experience changes in appetite or sleep patterns
  • Experience feelings or guilt and despair 
  • Experience self doubt
  • Feel empty or worthless 
  • Have a difficult time concentrating 
  • Lack energy
  • Lose interest in everyday activities 
  • Show poor memory 

What is borderline personality disorder (BPD)?

BPD is characterized by a pattern of instability in behavior, mood and sense of self. It can seriously impact a person’s ability to function on a daily basis in a way that bipolar disorder does not. Symptoms for BPD can make it difficult for an individual to maintain stable relationships. People with BPD have high rates of comorbid disorders, according to the National Library of Medicine, and often experience co-occurring disorders such as mood disorders, anxiety disorder, substance abuse disorders and eating disorders. 
Symptoms of BPD include:
  • Feelings of emptiness
  • Impulsiveness
  • Inability to manage anger 
  • Intense fear of abandonment
  • Mood swings involving anger and depression, usually due to stressful events or relationships
  • Poor self-image
  • Tendency to view people and situations as either "all good" or "all bad"
  • Tendency to commit self-harm or show suicidal behavior 
  • Unpleasant emotions
  • Unstable and intense relationships

What are the differences between bipolar disorder and borderline personality disorder?

While bipolar disorder and BPD share similar risk factors – such as genetics and the structure of their brains in contrast to people who do not have a disorder – they are marked by key differences. 
Bipolar disorder mood swings are triggered by manic or depressive episodes. When people with bipolar disorder are not experiencing an episode, they are typically stable in a way that people with BPD never are. People with bipolar disorder can function pretty well in their daily lives when they are in between episodes, and the stability they demonstrate with their relationships and at their jobs is typically not seen in a person with BPD. Mood swings are also more random than those of BPD, which usually revolve around a person’s own interpersonal conflicts.
Age at onset is another key factor; symptoms of BPD often start appearing during adolescence while bipolar disorder symptoms are more likely to start when a person just enters adulthood.

How treatment differs between BPD and bipolar disorder

Research has found bipolar disorder to be a biproduct of the biology of the nervous system, historically making it more responsive to medication. In addition to the biology of the brain and nervous system, BPD pathology strongly involves the psychological level of the mind. A more biological condition like bipolar doesn’t share these same psychological aspects, or ways of seeing the world and analyzing sense of self the way BPD does.
One way to note the fundamental difference between the two disorders, albeit an oversimplified way, is bipolar disorder is more about the brain while BPD is more about the mind. This is why first-line treatment for BPD usually focuses less on medication and more on psychotherapy, to attempt to change patterns of self-destructive behavior and help the patient better understand their feelings.
Both illnesses can be treated successfully. As noted, bipolar disorder treatment focuses on medication management, which often includes mood stabilizers, antipsychotics, or a combination of cognitive behavioral therapy with a mood stabilizer, such as an antipsychotic or antidepressant.
The three most common types of psychotherapy relied on to treat BPD include:
It is essential for patients with BPD to talk to their primary care provider (PCP) about referring them to a specialist as those with BPD are too often treated for depression or bipolar disorder or misdiagnosed. 
As bipolar disorder and BPD are each risk factors for suicidal behavior, patients with co-occurring bipolar disorder and BPD present with a higher suicide risk. Call or text the 988 Suicide & Crisis Lifeline for support anytime 24/7 if you or someone you know may be experiencing thoughts of suicide.
Photo credit: Getty Images
Read more:
MI Blues Perspectives is sponsored by Blue Cross Blue Shield of Michigan, a nonprofit, independent licensee of the Blue Cross Blue Shield Association