Borderline Personality Disorder (BPD) is a psychological disorder affecting about 1 to 2% of the population. It is considered a "personality disorder" by the American Psychiatric Association's Diagnostic and Statistical Manual, 4th edition (DSM-IV). Personality disorders are defined as typically beginning in adolescence or early adulthood and continuing over many years. Personality disorders often cause a great deal of distress and interfere with a person's ability to achieve fulfillment in relationships, work, or school.

Individuals with BPD suffer from “emotion dysregulation” which is the tendency to experience frequent and intense emotions. They often feel like they are on an “emotional roller coaster.” Impulsivity is a common problem for individuals with BPD. Impulsivity can occur in a number of different areas and may include: drug and alcohol use, reckless spending, shoplifting, risky sexual behaviors, and intentional self-injury. Individuals with BPD often describe having chaotic and intense relationships with others, including romantic partners, family members, and friends. Furthermore, men and women with BPD often describe uncertainty about their own identity- a feeling that they don’t know who they really are, or that their conception of who they are frequently changes.

Individuals with BPD often suffer from other psychological problems, including depression, substance use, post-traumatic stress disorder, bipolar disorder, and eating disorders.