Nine symptoms of this disorder are described in the Diagnostic and Statistical Manual; you must show five of these to qualify for the diagnosis. To summarize these symptoms, I would say they describe the presence of extremely intense, unstable emotions, including anger, unstable relationships marked by deep fear of abandonment, unstable self-image accompanied by impulsive behaviors in areas like spending, substance abuse or sex, episodes of dissociation, and recurrent suicidal threats or gestures and self-mutilation.

A 2008 study of nearly 35,000 adults found that 5.9% had been given a borderline personality disorder diagnosis. This translates to about 18 million Americans.