Psychological distress following marital separation interacts with a polymorphism in the serotonin transporter gene to predict cardiac vagal control in the laboratory

Abstract

Marital separation is linked to negative mental and physical health; however, the strength of this link may vary across people. This study examined changes in respiratory sinus arrhythmia (RSA), used to assess cardiac vagal control, in recently separated adults (N = 79; M time since separation = 3.5 months). When reflecting on the separation, self-reported psychological distress following the separation interacted with a polymorphism in the serotonin transporter gene (5-HTTLPR) and a relevant single nucleotide polymorphism (SNP), rs25531, to predict RSA. Among people reporting emotional difficulties after the separation, those who were homozygous for the short allele had lower RSA levels while reflecting on their relationship than other genotypes. The findings, although limited by the relatively small sample size, are discussed in terms of how higher-sensitivity genotypes may interact with psychological responses to stress to alter physiology.

Keywords: Divorce; Heart rate variability; Marital separation; Respiratory sinus arrhythmia; Serotonin transporter gene (5-HTTLPR); Single nucleotide polymorphism.

Figure 1

Simple slope decomposition of the interaction between genotype and IES-R (after accounting for relevant covariates) predicting Respiratory Sinus Arrhythmia (RSA) levels during the Divorce-specific Mental Activation Task. Figure 1a depicts RSA when considering genotype as the moderator of interest; Figure 1b reverses the comparison and treats IES-R scores as the moderator. Short Allele = homozygous S′ carriers, Long Allele = S′L′ + L′L′ carriers. RSA = Respiratory Sinus Arrhythmia; IES-R = Impact of Events Scale Revised. Simple slope decompositions are illustrated for people scoring 1 SD +/- below the mean on the IES-R.