The 5-HTTLPR polymorphism modulates the association of Serious Life Events and impulsivity in patients with Borderline Personality Disorder

Introduction: In the etiology of Borderline Personality Disorder (BPD) and one of its key features impulsivity, a general disease model of interacting genetic and environmental factors has been proposed. Regarding environmental factors, serious life events (SLE) are of major importance in the development of BPD. Genetically, impulsivity has been linked to an over-representation of the short (S) allele of the serotonin transporter promoter-linked polymorphic region polymorphism (5-HTTLPR). Methods: 159 BPD patients from Germany were included in the study. Impulsivity was assessed by the Barratt Impulsiveness Scale (BIS), SLEs by the PTSD-section included in the Munich-Composite International Diagnostic Interview (M-CIDI). We analyzed 1) the effects of SLEs on impulsivity; and 2) modulating effects of the 5-HTTLPR polymorphism on the association between SLEs and impulsivity. Results/Discussion: Regression analyses confirmed a decreasing effect of childhood sexual abuse on BIS sum score. Regarding the 5-HTTLPR polymorphism, all SLEs except for rape were associated with a decrease of impulsivity in SS/SL carriers and an increase in LL carriers. This study analyzing a specific gene x environment interaction in BPD patients suggests an interaction between SLEs and the 5-HTTLPR S/L polymorphism in the regulation of impulsivity in BPD patients. Clinical and research implications are discussed.