Loneliness is related to mental and somatic health outcomes, including borderline personality disorder. Here, we analyze the sources of variation that are responsible for the relationship between borderline personality features (including four dimensions, affective instability, identity disturbance, negative relationships, self-harm and a total score) and loneliness. Using genetically informative data from two large nonclinical samples of adult twin pairs from Australia and the Netherlands (N = 11,329), we estimate the phenotypic, genetic and environmental correlations between self-reported borderline personality features and loneliness. Individual differences in borderline personality and loneliness were best explained by additive genetic factors with heritability estimates h2 = 41% for the borderline personality total score and h2 = 36% for loneliness, with the remaining variation explained by environmental influences that were not shared by twins from the same pair. Genetic and environmental factors influencing borderline personality (total score and four subscales separately) were also partial causes of loneliness. The correlation between loneliness and the borderline personality total score was rph = .51. The genetic correlation was estimated at rg = .64 and the environmental correlation at re = .40. Our study suggests common etiological factors in loneliness and borderline personality features.

中文翻译：

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边缘性人格障碍特征和孤独感个体差异的遗传和环境原因是部分共有的

孤独与心理和身体健康结果有关，包括边缘性人格障碍。在这里，我们分析了导致边缘人格特征（包括四个维度，情感不稳定性、身份障碍、消极关系、自我伤害和总分）与孤独感之间关系的变异来源。使用来自澳大利亚和荷兰的两个大型非临床成年双胞胎样本的遗传信息数据（ñ= 11,329），我们估计了自我报告的边缘人格特征与孤独感之间的表型、遗传和环境相关性。边缘人格和孤独感的个体差异最好用具有遗传力估计的加性遗传因素来解释H2= 41% 的边缘人格总分和H2= 36% 的孤独感，其余的变化由来自同一对双胞胎的双胞胎不共享的环境影响解释。影响边缘人格的遗传和环境因素（总分和四个分量表分别）也是孤独的部分原因。孤独感与边缘人格总分的相关性为r酸碱度= .51。遗传相关性估计为rG= .64 和环境相关性re= .40。我们的研究表明了孤独和边缘人格特征的常见病因。