What are the differences between bipolar and borderline personality disorder?

October 26, 2023
8 minute read

Mental health encompasses a wide spectrum of conditions, each with its own unique characteristics and complexities.

Among some of the most frequently discussed mental health conditions are bipolar disorder (BD) and borderline personality disorder (BPD). While these disorders do exhibit some similarities - most notably a degree of overlapping symptoms - they are distinct conditions, each with their own sets of challenges and approaches to treatment.  

Understanding the distinctions between these conditions is essential for fostering awareness and offering better support for those around us living with these conditions.  

Read on as we delve into the major differences between bipolar disorder and borderline personality disorder, examining areas of symptom overlap and distinctions, plus approaches to treatment.  

Mood disorders versus personality disorders

One of the key differences between bipolar disorder and borderline personality disorder relates to their categorisation. Bipolar disorder falls under the category of mood disorders, a class of conditions primarily characterised by severe changes in mood. Other mood disorders include major depressive disorder and persistent depressive disorder.  

By contrast, borderline personality disorder is a personality disorder; a class of disorders marked by patterns of behaviour that deviate from societal norms and expectations, resulting in significant distress and challenges to the affected individual. Other examples of personality disorders include narcissistic personality disorder, paranoid personality disorder and obsessive-compulsive personality disorder.  

What is bipolar disorder?

Bipolar disorder (previously known as manic depression) is characterised by the presence of intense, prolonged mood swings that can range from extreme highs (also known as mania) to extreme lows of depression. One of the hallmarks of bipolar disorder is that these mood swings appear in episodes. Sufferers of bipolar disorder cycle through episodes of depression and mania. Often, periods of a stable, normal mood can occur in between. These patterns affect individuals differently; some may experience rapid cycling between episodes, while in other cases mixed states can be experienced, where a person experiences symptoms of depression coupled with overactivity.  

During depressive episodes, individuals suffering from bipolar disorder can experience a range of depression symptoms including:

  • Intense feelings of worthlessness, self-doubt, pessimism  
  • Lethargy and lack of energy
  • Feelings of guilt and despair  
  • Lack of appetite
  • Insomnia  
  • Suicidal thoughts  
  • Disturbed, illogical thinking and even hallucinations  
  • Loss of interest in normal activities (anhedonia)

During a manic episode, symptoms can include:

  • Abnormally elevated mood, euphoria and energy levels  
  • Talking quickly, inflated ego and feelings of grandiosity  
  • Reduced need for sleep
  • Tendency to engage in risky or destructive behaviour such as gambling or substance abuse
  • Disturbed thinking that can lead to uncharacteristic behaviour  

What is borderline personality disorder?

Borderline personality disorder shares some similarities with bipolar disorder in terms of mood swings and impulsive behaviour. However, individuals with borderline personality disorder experience more rapid shifts in their emotions compared to those with bipolar disorder, leading to abrupt changes in mood, relationships, self-image and behaviour. Borderline personality disorder is also characterised by heightened sensitivity to rejection, tumultuous relationships and difficulties in managing emotions.  

Individuals with BPD exhibit a wide array of symptoms, which can be broadly categorised into four groups:

  1. Emotional instability - marked by experiences of rage, shame, panic and terror
  1. Disordered thought patterns - including distressing, unfounded thoughts, auditory hallucinations and paranoia
  1. Impulsive behaviour - involving a tendency toward self-harm and urges to engage in risky activities
  1. Unstable relationships - driven by a fear of abandonment, resulting in "love-hate" dynamics with others

Not everyone with borderline personality disorder experiences all of these symptoms, as the severity of the condition can vary from person to person. Individuals that suffer from borderline personality disorder can react disproportionately to stressful or emotional events, often triggering symptoms.  

Causes of bipolar disorder and borderline personality disorder

Much like most mental health conditions, the exact causes of both bipolar disorder and borderline personality disorder are not fully clear.  

In the case of bipolar disorder, it is believed that the causes are an interplay of genetics and triggers such as abuse or extremely emotionally taxing events, such as breakdown of relationships of the death of a loved one. Additionally, there is also evidence that individuals with bipolar disorder present imbalances and neurotransmitter dysregulation in their brains.  

When it comes to borderline personality disorder, we once again see an interplay of various causal factors that aren’t fully understood. Genetics, neurotransmitter imbalance, problems with brain development and environmental factors such as trauma and neglect during childhood are all thought to play a role in the development of borderline personality disorder.  

Treating bipolar disorder and borderline personality disorder

The approach to treatment for the two disorders is largely different. In the case of bipolar disorder, medication such as mood stabilisers (like lithium) and antipsychotics are often used in conjunction with psychotherapy and lifestyle interventions.  

By contrast, the treatment of borderline personality disorder places a much higher emphasis on psychotherapy, though medications can be used to treat some of the symptoms that accompany the condition. One of the staples of psychotherapy for BPD is dialectic behaviour therapy (DBT), which seeks to help people regulate their emotions, be more mindful of their thoughts and behaviour, and have more successful relationships with others.  

Learn more

To find out more about these conditions and how you can support someone close to you, explore more via the NHS.

Do you have any additional questions? Get in touch with our friendly, professional pharmacy team who can offer you guidance and advice.

Content last reviewed on:
October 26, 2023
Next review date:
October 26, 2025
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