Personality disorder is a sort of repelling term as it may sound like having bad character. But it doesn't really mean that. First of all, personality means the typical way that somebody thinks, feels, and reacts. As you can tell by experience, people have different approaches. For example, some are social butterflies and like mixing with others while others are reserved and like to keep to themselves. Some are very laid-back while others tend to get nervous easily. A bunch of people are curious and like to test everything. Others are the opposite and like to stick to their old routines. Some are competitive and dominating while others are timid and accommodating. Finally, some are stubborn and self-disciplined while others are flexible or may lose their interest easily. Personality disorder is when you're not happy with your usual way of thinking, feeling, and reacting; or when this interferes with your relationship, work, or everyday life.
There are several personality disorders. Among them, borderline personality disorder (BPD) is the most dramatic one. It's known by four core features: emotional instability, interpersonal turmoil, identity issue, and impulsivity. A person with BPD shows rapid mood swings; for example, they may start the day in a great mood but then may suddenly feel upset, sad, or flat. Their relationships also have lots of ups and downs. They are scared of abandonment. Their feeling toward others may shift swiftly from love to hate, or they may have mixed feelings toward others. People with BPD may feel like that they don't have a solid sense of self, feel fragmented, or feel like they have multiple personalities. The instability in mood, relationship, and identity is quite frustrating and overwhelming. So they most often take impulsive actions to feel better. Unfortunately, some of these impulsive actions are quite dangerous or self-destructive; such as drug abuse, careless intimacy, or intentional self-harm.
Borderline personality disorder typically causes significant problems in life. People with BPD tend to lose jobs and break up frequently. They may harm themselves or attempt suicide when depressed or frustrated. Some may get irritable and aggressive during relationship turmoil. Impulsive decisions can put them at great risk too. But above all, alcohol and drug abuse can complicate the illness severely. Those who don't take drugs are more likely to have favourable outcomes.