Borderline personality disorder more common than schizophrenia

According to the National Institute of Mental Health, borderline personality disorder (BPD) is more common than schizophrenia or bipolar disorder and is estimated to affect 2 percent of the population.

In a new study, a University of Missouri researcher and Dutch team of research collaborators found that genetic material on chromosome nine was linked to BPD features, a disorder characterized by pervasive instability in moods, interpersonal relationships, self-image and behavior, and can lead to suicidal behavior, substance abuse and failed relationships.

"The results of this study hopefully will bring researchers closer to determining the genetic causes of BPD and may have important implications for treatment programs in the future," said Timothy Trull, professor of psychology in the MU College of Arts and Science. "Localizing and identifying the genes that influence the development of BPD will not only be important for scientific purposes, but will also have clinical implications."

In an ongoing study of the health and lifestyles of families with twins in the Netherlands, Trull and colleagues examined 711 pairs of siblings and 561 parents to identify the location of genetic traits that influences the manifestation of BPD. The researchers conducted a genetic linkage analysis of the families and identified chromosomal regions that could contain genes that influence the development of BPD. Trull found the strongest evidence for a genetic influence on BPD features on chromosome nine.

In a previous study, Trull and research colleagues examined data from 5,496 twins in the Netherlands, Belgium and Australia to assess the extent of genetic influence on the manifestation of BPD features. The research team found that 42 percent of variation in BPD features was attributable to genetic influences and 58 percent was attributable to environmental influences, and this was consistent across the three countries. In addition, Trull and colleagues found that there was no significant difference in heritability rates between men and women, and that young adults displayed more BPD features then older adults.

"We were able to provide precise estimates of the genetic influence on BPD features, test for differences between the sexes, and determine if our estimates were consistent across three different countries," Trull said. "Our results suggest that genetic factors play a major role in individual differences of borderline personality disorder features in Western society."