Borderline personality disorder is a mental health condition that affects the way people feel about themselves and others, making it hard to function in everyday life. It includes a pattern of unstable, intense relationships, as well as impulsiveness and an unhealthy way of seeing themselves. Impulsiveness involves having extreme emotions and acting or doing things without thinking about them first. People with borderline personality disorder have a strong fear of abandonment or being left alone. Even though they want to have loving and lasting relationships, the fear of being abandoned often leads to mood swings and anger. It also leads to impulsiveness and self-injury that may push others away. Borderline personality disorder usually begins by early adulthood. The condition is most serious in young adulthood. Mood swings, anger and impulsiveness often get better with age. But the main issues of self-image and fear of being abandoned, as well as relationship issues, go on. If you have borderline personality disorder, know that many people with this condition get better with treatment. They can learn to live stabler, more-fulfilling lives.