Intense emotional fluctuations are usually present and frequently involve extreme anger or depression. Affected persons develop a pattern of relationships that involves oscillating between closeness and distance, often with a fear of abandonment. Transient psychotic episodes may also lead to extreme suspicion. In the past decade, research has focused on the underlying causes of this disorder. Although no one cause has been identified, several factors appear to contribute.
Researchers consistently find a higher rate of sexual abuse in borderline patients.
Prior physical and verbal abuse also appears linked to higher rates of occurrence. Certain patterns of overinvolvement between parent and child may be causative factors. Some studies have shown that parents may have difficulty allowing their child to grow up and become separate. Borderline patients may thus fear situations where they must be independent and autonomous. However, it would be incorrect to link this disorder to any one type of parent-child interaction.