There are many similarities between borderline personality disorder (BPD) and bipolar disorder, but these mental health conditions greatly differ in their causes, symptoms, and treatments. It’s important to understand the difference between these two mental health conditions in order to receive a correct diagnosis and effectively help individuals manage their symptoms.

Borderline personality disorder is a personality disorder characterized by long-term patterns of instability in behaviors, sense of self, and relationships. According to the National Institute of Mental Health, around 1.4% of adults in the United States are diagnosed with borderline personality disorder. The main symptoms of the disorder include fear of abandonment, distorted self-image, impulsive behaviors, displays of anger, unstable relationships, intense mood shifts, and self-harm. People with borderline personality disorder may experience temporary periods, usually between a few hours to a few days, that includes mood swings, increased impulsive behavior, rage, and dissociative symptoms. There isn’t one specific cause of borderline personality disorder. According to JAMA Network, genetics play a significant role, with a heritability of 55%. Additionally, traumatic and difficult events like sexual or physical abuse, family instability, and separation from caregivers can influence the development of this condition. The main form of treatment is psychotherapy, with dialectical behavioral therapy (DBT) being a commonly used approach. This can be a great treatment option for people with borderline personality disorder because it involves individual therapy and skills-training groups with the goal of managing intense emotions, improving interpersonal relationships, and practicing mindfulness.

Bipolar disorder is a mood disorder that causes extreme shifts in mood and energy. The two main subtypes of the disorder are bipolar I disorder and bipolar II disorder. Bipolar I disorder involves an individual experiencing at least one manic episode. Bipolar II disorder involves an individual experiencing at least one hypomanic episode and at least one major depressive episode. Bipolar episodes vary greatly in duration and are characterized by unpredictable behavior. Symptoms of manic and hypomanic episodes may include being more active than usual, sleeplessness, being extremely talkative, and racing thoughts. Symptoms of depressive episodes may include feelings of low self-worth, changes in appetite, changes in sleep patterns, lethargy, and thoughts of death. Similar to borderline personality disorder, there isn’t a single known cause of bipolar disorder. According to the Cleveland Clinic, some factors that influence bipolar disorder include genetics, especially having a first-degree relative with the disorder, epigenetics, and brain chemistry. The main treatment options that may help reduce symptoms of depressive and manic episodes are cognitive behavioral therapy (CBT) and medication, particularly mood stabilizers. 

Borderline personality disorder and bipolar disorder are both serious, lifelong mental health conditions that share several similar symptoms, but significantly differ in their main characteristics. Due to their overlapping symptoms and the potential for misdiagnosis, receiving an accurate diagnosis is crucial. With a precise diagnosis, individuals can get treatment tailored to their specific needs and successfully manage their symptoms.

Article written by: Adriana Kirakosyan “My name is Adriana Kirakosyan and I have a deep love for learning and engaging with different mental health topics. I received my Bachelor’s of Arts in Psychology from University of California, San Diego in June 2026, and I will continue my education by pursuing a master’s degree in the near future.”