Borderline personality disorder is characterized by poor self-image, a feeling of emptiness, and great difficulty coping with being alone. People with this disorder have highly reactive and intense moods, and unstable relationships. Their behavior can be impulsive. They are also more likely than average to attempt or commit suicide. Sometimes, without intending to commit suicide, they harm themselves (for example, cutting or burning) as a form of self-punishment or to combat an empty feeling.
When stressed, people with borderline personality disorder may develop psychotic-like symptoms. They experience a distortion of their perceptions or beliefs rather than a distinct break with reality. Especially in close relationships, they tend to misinterpret or amplify what other people feel about them. For example, they may assume a friend or family member is having extremely hateful feelings toward them, when the person may be only mildly annoyed or angry.
People with borderline personality disorder have a deep fear of abandonment. They compete for social acceptance, are terrified of rejection and often feel lonely even in the context of an intimate relationship. Therefore, it is more difficult for them to manage the normal ups and downs of a romantic partnership. Impulsive, self-destructive behavior may be an attempt to ward off rising anxiety related to the fear of being left alone.
The flip side of the fear is the hope that a relationship will be completely soothing. People with this disorder may idealize a family member, romantic partner or friend, and then become enraged when an inevitable disappointment occurs. They might hold that person responsible for the pain they feel and devalue the relationship.
Most experts believe personality disorders develop as a result of both environmental and biological factors. Early research on this disorder focused on problems in growing up, for example, having gone through abuse or neglect as a child. A significant number of people with symptoms of this disorder have reported such a history in childhood.
Later research has suggested that people with this disorder may have inborn difficulties in regulating their anxiety or moods. They may be more vulnerable to loss or more sensitive to stress than average.
Scientists have begun to see how these characteristics are reflected in the brains of people with borderline personality disorder. Some people with this disorder have an exaggerated startle response to unpleasant stimuli. Brain regions involved in managing fear and controlling aggressive responses function differently in people with borderline personality disorder when compared to people without the disorder. Researchers have also discovered distinctive patterns in hormone levels and the immune system in people with the disorder.
It is quite common for people with borderline personality disorder to also have a mood disorder, eating disorder or substance abuse problem. The person may turn to alcohol or drugs to escape from painful, uncontrollable emotions.
Three times as many women as men are diagnosed with borderline personality disorder. It occurs in about 2% of the population in the United States.