Borderline personality disorder (BPD) is a condition that causes patients to have periods of unstable emotions that can seriously affect their quality of life. Patients with BPD have great difficulty controlling their emotions and impulses, and may experience frequent mood swings. As a result, patients tend to have unstable relationships and are distressed by emotional emptiness and fears of abandonment.

Patients with BPD may be calm for long periods of time before suffering episodes of extreme disruption that may last from a few hours to an entire day or longer. They may have a poor sense of self-identity and can suddenly shift their goals, values and opinions. Individuals also may alter plans regarding their career, lifestyle or type of friends. People with BPD sometimes view themselves as bad or unworthy, and tend to feel misunderstood or mistreated. They have a tremendous need for love that is matched by a fear of abandonment. Often, they will react with extreme rage or despair when they feel hurt by a loved one. 

About 2 percent of the general population has BPD, according to the American Psychiatric Association (APA). However, this is based on limited information.  In many cases, BPD is not immediately apparent to the patient. In fact, patients are more likely to seek help at the urging of a family member or friend. Patients who visit a primary or mental healthcare physician (e.g., psychiatrist) are likely to be asked a series of questions that may help the physician make a BPD diagnosis.