Co-Medical Director / Founding Member
Dr. Ehab Abdallah is the Managing Partner and MD Psychiatrist at Legacy Recovery Center bringing a wealth of expertise to his role. He obtained his medical degree from Alexandria University in Egypt and completed his residency in psychiatry at West Virginia University. Dr. Abdallah is triple board-certified in General Psychiatry, Consultation-Liaison (Psychosomatic) Psychiatry, and Addiction Psychiatry and Medicine.
With a specialized focus on addiction medicine, Dr. Abdallah has extensive experience treating individuals facing complex medical and psychiatric conditions. His dedication to high-quality care and genuine commitment to his patients’ well-being make him an invaluable member of the team.
In addition, Dr. Abdallah is a Fellow of the American Psychiatric Association and serves as a clinical assistant professor of psychiatry at the University of Arizona, where he educates and mentors medical students and residents.
It can be confusing to tell the difference between Borderline Personality Disorder (BPD) and Bipolar Disorder (BD) as they share the same initials and have some symptoms in common.
Even for medical professionals it can be difficult to correctly diagnose these disorders because they are sometimes found together and have overlapping symptoms. There is an ongoing debate over whether BPD should be considered as part of the spectrum of BD disorders. For now, they are treated separately.
The key difference is that BPD is a personality disorder, while BD is a mood disorder. The common features most frequently observed are emotional instability, impulsivity, troubled relationships, distractibility, irritability, suicidality, flight of thoughts, and childhood adversity [1]. According to NAMI, BPD affects 1.4% of the population, and BD affects 2.8% [2] [3].
However, the conditions under which these disorders occur and the way they present are quite different. In this article, I explain what each disorder consists of, its main symptoms, and forms of treatment.
Understanding the Core of Each Condition
Borderline Personality Disorder: A Personality Disorder
BPD is a pattern of instability in a person’s self-image, interpersonal relationships, and emotions. Individuals are highly reactive, leading to intense emotional responses to interpersonal events. Pervasive instability and a deep-seated fear of abandonment are central to BPD. It is called ‘borderline’ because it involves mood, anxiety, and psychotic symptoms. It usually develops in adolescence.
Bipolar Disorder: A Mood Disorder
BD is a biological brain disorder primarily affecting a person’s energy, activity, and mood levels. It is cyclical, alternating between high (mania) and low (depression), or cycles between the two. Episodes are distinct, sustained periods (days to months) that represent a clear change from a person’s baseline.
Causes of Both
The causes are not clearly known, although it is believed to be due to [4].
- Genetic risks and family history of BPD or bipolar disorder
- Early environmental stress, like child abuse or trauma, especially in BPD
- Changes in brain structure, size, or function
Key Differences: A Side-by-Side Comparison
Classic BD Type 1 is easier to distinguish from BPD than Bipolar 2 since true manic symptoms (often with hallucinations) are the defining characteristic of Type 1 and these symptoms are not seen in the same way in BPD.
Bipolar Type 2 is a more challenging diagnosis to differentiate from BPD, because the classic manic episode is absent. So, on the surface, it can appear more like BPD [5].
The main differences include:
The Nature of Mood Shifts
BPD: Rapid, intense, reactive, short-lived mood swings. Emotions can change drastically within hours or even minutes, often in direct response to interpersonal stress (e.g., a perceived slight, fear of rejection), which can severely impact everyday life.
These moods alternate between a desperate neediness for others and an intense anger or dismissal of others when feeling rejected. Mood can shift rapidly from a negative, depressed state to an elated one, but primarily negative feeling states.
Bipolar: Cyclical, sustained episodes. Moods (mania/hypomania or major depression) are like distinct “seasons” that last for extended periods from weeks to months.
Primary Triggers
BPD: Triggers are almost always interpersonal. The main trigger is the real or perceived threat of abandonment, rejection, or invalidation.
Bipolar: Episodes can appear out of the blue or be triggered by sleep disruption, life changes, or substance use. They are less tied to specific social interactions.
Self-Image and Relationships
BPD: The primary symptom of BPD is a chronically unstable sense of self. People with BPD experience a cycle of varying self-image, moods, and behaviors. Relationships are often intense and unstable. They often have a strong pattern of idealization. One minute someone is “perfect” and the next minute they are “terrible”.
Bipolar: Self-image may shift with the mood episode. During depression, they may feel worthless, and during mania, they may feel grandiose. Between episodes, self-image is generally more stable.
The Role of Impulsivity
BPD: Self-harm, suicidal gestures, and reckless spending are predominant impulsive behaviors. This is often a persistent coping mechanism to manage feelings of emptiness, abandonment, or other forms of intense emotional pain.
Bipolar: Impulsivity (spending, sex, risky business) is typically clustered during manic or hypomanic episodes.
This table compares the main features of each disorder [4] [5] [6] [7].
Aspect | Borderline Personality Disorder (BPD) | Bipolar Disorder (BD) |
Disorder Type | Personality disorder | Mood Disorder |
Mood Changes | Rapid, reactive | Episodic, longer lasting |
Trigger | Interpersonal stress | Often spontaneous |
Relationship Pattern | Unstable, intense | Stable outside episodes |
Self-image | Fluctuating | Stable, mood-dependent |
Impulsivity | Brief, distress-driven | Manic episode-associated |
Main Treatments | Psychotherapy (DBT, etc.) | Medication and therapy |
Overlapping Similarities | ||
Mood Swings Extreme Emotional States Impulsive Behaviors Suicidal Ideation and Self-Harm | ||
Treatment: Why Getting the Diagnosis Right Matters
It’s important to have a correct diagnosis from a qualified medical professional (typically a psychiatrist) as the treatment paths of each are quite different.
BPD Treatment: Dialectical Behavior Therapy (DBT) is the gold standard and builds emotional regulation and interpersonal skills. Medication may be used for co-occurring symptoms.
Bipolar Treatment: Focuses on mood stabilizers (e.g., Lithium, valproic acid) and/or antipsychotics (Quetiapine, Aripiprazole, Olanzapine) to prevent the highs and lows. Interpersonal and Social Rhythm Therapy (IPSRT) was developed for BD, and is supportive.
Consequence of Misdiagnosis: Treating BPD with only mood stabilizers misses the mark. Treating Bipolar only with therapy and without medication can be ineffective and dangerous.
Get Expert Help at Legacy Recovery Center
Legacy Recovery Center is a highly rated, premier addiction and mental health treatment center in Arizona. Legacy is owned and operated by two psychiatrists with over 40 years of combined experience, as well as a robust therapeutic team.
We’re unique among residential treatment centers thanks to our ability to help people suffering from mental health and/or substance abuse issues. Our expert psychiatric team is equipped to treat multiple issues concurrently, focusing on your specific needs. Contact us today!
Sources
[1] Durdurak, B. B., Altaweel, N., Upthegrove, R., & Marwaha, S. (2022). Understanding the development of bipolar disorder and borderline personality disorder in young people: a meta-review of systematic reviews. Psychological medicine, 52(16), 1–14. Advance online publication.
[2] NAMI. nd. Personality Disorders.
[3] NAMI. nd. Bipolar Disorder.
[4] Cleveland Clinic. 2025. Borderline Personality Disorder vs. Bipolar Disorder. Clevelandclinic.org
[5] Duckworth K. 2017. Borderline Personality Disorder and Bipolar Disorder: What’s the Difference? NAMI.org
[6] Huizen J. 2024. What’s the difference between borderline personality disorder and bipolar disorder? Medicalnewstoday.com
[7] Allison C. 2022. Understanding the Difference Between Bipolar and Borderline Personality Disorder. New York-Presbyterian Health Matters.
