Familial resemblance of borderline personality disorder features: genetic or cultural transmission?

Marijn A Distel,Catherine A Derom,Timothy J Trull,Dorret I Boomsma,Nicholas G Martin,Irene Rebollo-Mesa,Gonneke Willemsen

doi:10.1371/journal.pone.0005334

Abstract

Borderline personality disorder is a severe personality disorder for which genetic research has been limited to family studies and classical twin studies. These studies indicate that genetic effects explain 35 to 45% of the variance in borderline personality disorder and borderline personality features. However, effects of non-additive (dominance) genetic factors, non-random mating and cultural transmission have generally not been explored. In the present study an extended twin-family design was applied to self-report data of twins (N = 5,017) and their siblings (N = 1,266), parents (N = 3,064) and spouses (N = 939) from 4,015 families, to estimate the effects of additive and non-additive genetic and environmental factors, cultural transmission and non-random mating on individual differences in borderline personality features. Results showed that resemblance among biological relatives could completely be attributed to genetic effects. Variation in borderline personality features was explained by additive genetic (21%; 95% CI 17–26%) and dominant genetic (24%; 95% CI 17–31%) factors. Environmental influences (55%; 95% CI 51–60%) explained the remaining variance. Significant resemblance between spouses was observed, which was best explained by phenotypic assortative mating, but it had only a small effect on the genetic variance (1% of the total variance). There was no effect of cultural transmission from parents to offspring.

Highlights

Borderline personality disorder (BPD) is characterized by emotional lability, impulsivity, interpersonal difficulties, identity disturbances, and cognitive impairments [1]
We examine the genetic and environmental influences on individual differences in BPD features using an extended twin-family design
A genetic model in which additive genetic effects (21.3%; 95% CI 16%– 26%), dominant genetic effects (23.9%; 95% CI 17%–31%) and unique environmental influences (54.9%; 95% CI 51%–60%) explained the variance in BPD features best explained the data

Summary

Introduction

Borderline personality disorder (BPD) is characterized by emotional lability, impulsivity, interpersonal difficulties, identity disturbances, and cognitive impairments [1]. BPD is associated with a number of negative outcomes, including suicidal behavior, frequent emergency room admissions, substance abuse, impaired occupational functioning, and poor quality of interpersonal relationships. Genetic research on individual differences in BPD has been limited to non-twin family studies and classical twin studies. Studies have consistently shown increased rates of BPD in family members of BPD patients [4,5,6], and twin studies of BPD reported heritability estimates around 40% [7,8,9]. Classical twin studies are important to detect whether there are genetic influences on BPD features. Spouses and parents of twins in the study several additional research questions can be answered

Methods

Results

Conclusion