Borderline Personality Disorder (BPD), also known as emotionally unstable personality disorder, is not a rare disorder. It affects about 2 percent of the population. In mental health clinics the prevalence rate is much higher! About 15 to 20 percent of psychiatric inpatients and about 10 percent of mental health outpatients have a borderline personality disorder. This personality disorder is very common among adolescent and young adults with the highest rates at the ages between 18 and 35. However the reason for hospitalization or treatment will very often be a different psychiatric problem like eating disorders, addiction problems, suicide attempts, depression or anxiety disorders. Very often patients with BPD have additional personality disorders. Women are diagnosed with Borderline personality disorder about 2 to 4 times more often than men. Men with similar problems or interactive styles are more often classified as having Antisocial Personality Disorder or Narcissistic Personality.