The changeable moods and unpredictable behaviour of people with borderline personality disorder (BPD) can lead to difficulties in relationships. However, there is little actual research to back this up. About 20-30% of people with borderline personality disorder are estimated to be in a relationship at any one time and researchers from the Institut Universitaire en Sante Mentale de Quebec looked into this issue more closely. They studied a sample of 35 couples where neither partner was affected. The partners filled out questionnaires about their personalities and how they thought their relationship was functioning. 68.7% of the couples in which the women suffered from BPD had frequent break-ups and reconciliations and nearly 30% of these couples dissolved their relationship. Nearly half of the men involved with a woman with BPD had at least one personality disorder. Couples with a partner with BPD had lower marital satisfaction, were less secure in their attachment to one another, had more communication problems and had higher levels of violence.
Bouchard, Sebastien ... [et al] - Relationship quality and stability in couples when one partner suffers from borderline personality disorder Journal of Marital and Family Therapy October 2009, 35(4), 446-455