Does 5-HTTLPR moderate the effect of the quality of environmental context on maternal sensitivity? Testing the differential susceptibility hypothesis

The nature of nurture: Darwinian and mendelian perspectives

Two perspectives on the nature of nurture are reviewed, one Mendelian and the other Darwinian, in an effort to draw links between the two and, thereby, integrate them in a developmental modern synthesis, mirroring the one that took place in biology early in the last century. Thus, the heritability of environmental measures and gene-X-environment interaction are discussed with respect to Mendelian nature before turning attention to Darwinian nature and thus the development of reproductive strategies and differential susceptibility to environmental influences. Conclusions are drawn with respect to both frameworks indicating that it is time to abandon the biology-is-destiny resistance to both approaches to studying and thinking about development, especially when it comes to the nature of nurture. Implications for the future development of the field of developmental psychopathology are highlighted.

Family instability, parenting, and child externalizing problems: Moderation by maternal sympathetic stress reactivity

This multi-method longitudinal study evaluated how changes in maternal sensitive parenting may operate as an indirect factor linking family instability and the development of child externalizing problems over time. This study also investigated how mothers' stress reactivity within the sympathetic nervous system (SNS) may moderate the association between family instability and the development of maternal sensitivity. Participants were 235 families with a young child (Mage = 2.97 years at the first measurement occasion) and these families were followed for two annual measurement occasions. Maternal sensitivity was observed during two discipline tasks (i.e., forbidden toy, discipline discussion tasks), and maternal SNS stress reactivity was indicated by their salivary alpha-amylase (sAA) reactivity to an interpersonal stressor. Findings revealed significant direct effects of family instability and family instability-x-sAA reactivity interaction in association with the change in maternal sensitivity over time. For both tasks, mothers with greater sAA reactivity exhibited stronger associations between family instability and the growth of their sensitivity. Tests of indirect effects indicated that change in maternal sensitivity operated as an indirect factor between family instability-x-sAA reactivity interaction and the change in child externalizing problems. The present findings have important implications for understanding parental and child sequelae associated with unstable family contexts.

Variation in the serotonin transporter genotype is associated with maternal restraint and rejection of infants: A nonhuman primate (Macaca mulatta) model

Studies show that maternal behaviors are mediated by the bivariate serotonin transporter (5-HTT) genotype, although the findings are mixed, with some studies showing that mothers with the s allele exhibit increased maternal sensitivity, while other studies show that mothers with the s allele show decreased maternal sensitivity. Nonhuman primate studies offer increased control over extraneous variables and may contribute to a better understanding of the effects of the 5-HTT genotype on maternal sensitivity. This study assesses the influence of 5-HTT genotype variation on maternal sensitivity in parenting in 125 rhesus macaque mothers (Macaca mulatta) during the first three-months of their infants' lives, an age well before typical infants undergo weaning. Mothers were genotyped for the 5-HTT genotype and maternal behaviors were collected, including neglectfulness, sensitivity, and premature rejections during undisturbed social interactions. Results showed that mothers homozygous for the s allele rejected their infants the most and restrained their infants the least, an indication that mothers with the s allele are more likely to neglect their infants' psychological and physical needs. These findings suggest that, at an age when an infant's needs are based on warmth, security, and protection, mothers with an s allele exhibit less sensitive maternal behaviors. High rates of rejections and low rates of restraints are behaviors that typically characterize premature weaning and are inappropriate for their infant's young age. This study is an important step in understanding the etiology of variability in maternal warmth and care, and further suggests that maternal 5-HTT genotype should be examined in studies assessing genetic influences on variation in maternal sensitivity, and ultimately, mother-infant attachment quality.

Parents' differential susceptibility to a "micro" parenting intervention: Rationale and study protocol for a randomized controlled microtrial

BACKGROUND

Given evidence that parenting can influence children's development, parenting interventions are often the strategy of choice when it comes to treating children's disruptive behavior problems-or preventing problems from developing in the first place. What remains under appreciated, however, is that some parents appear to be more responsive to interventions to foster skilled parenting than others. Notable in this regard is the ever-increasing observational and, perhaps more importantly, experimental evidence indicating that some children prove more susceptible to parenting interventions than others. So, while the experimental evidence clearly indicates that "susceptibility factors" which children carry seem to affect their likelihood of benefiting from a parenting intervention (and other environmental influences), what remains unclear is why the parenting interventions in question prove more effective in changing the behavior of some parents more than others. Could it be as a result of their own parental characteristics?

OBJECTIVE

The Parfective Microtrial in a randomized controlled microtrial, in which we focus not just on parental (and child) responsiveness but also on an underlying physiological mechanism hypothesized to contribute to heightened susceptibility to parenting interventions.

METHODS

Participants are 120 families, with children aged 4-5 years, recruited from the community. Of these, 60 are randomly assigned to the "micro" intervention condition (i.e., immediate positive parenting feedback) and 60 families to the care-as-usual control condition. Assessments in both conditions will be conducted at baseline (pretest), after 2 weeks (posttest), and after 4 weeks (follow-up). Primary outcomes are the hypothesized moderating effects of physiology on the anticipated "micro" intervention effect (i.e., decrease in negative parenting behavior and/or increase in positive parenting behavior). Secondary outcomes are the observed (changes in) child behavior in response to the parenting intervention, such that those parents and children-in the same family-who manifest these physiological attributes will prove most susceptible to the beneficial effects of the intervention.

TRIAL REGISTRATION

This study protocol is registered at ClinicalTrials.gov (NCT05539170).

Parenting and the Serotonin Transporter Gene (5HTTLPR), Is There an Association? A Systematic Review of the Literature

The current systematic review examines whether there is an association between the genetic 5-HTTPLR polymorphism and parenting, and the mechanisms by which this association operates. The literature was searched in various databases such as PubMed, Scopus, and ScienceDirect. In line with our inclusion criteria, nine articles were eligible out of 22. Most of the studies analysed in this review found an association between 5HTTLPR and parenting. Four studies found a direct association between 5-HTTLPR and parenting with conflicting findings: two studies found that mothers carrying the short variant were more sensitive to their infants, while two studies found that parents carrying the S allele were less sensitive. In addition, several studies found strong interaction between genetic and environmental factors, such as childhood stress and disruptive child behaviour, quality of early care experiences, poor parenting environment, and quality of the environment. Only one study found an association between children's 5HTTLPR and parenting. Parenting can be described as a highly complex construct influenced by multiple factors, including the environment, as well as parent and child characteristics. According to the studies, maternal 5-HTTLPR polymorphism is most likely to be associated with sensitive parenting.

Paternal antisociality and growth in child delinquent behaviors: Moderating effects of child sex and respiratory sinus arrhythmia

Children of fathers with antisocial personality disorder (ASPD) are at risk for developing delinquency, and both biological and environmental mechanisms contribute. In this study, we test parasympathetic nervous system (PNS) function as a vulnerability/sensitivity attribute in predicting intergenerational associations between fathers' antisociality and children's delinquency scores. We followed 207 children (ages 8-12 years at intake; 139 boys) across three annual assessments. Fathers' antisociality was measured via maternal reports on the Family Interview for Genetic Studies (FIGS). At Year 1, children's resting respiratory sinus arrhythmia (RSA) was measured. At Years 1, 2, and 3, child delinquent behaviors were assessed using the delinquency subscale of the Youth Self-Report. At age 8, boys' delinquency scores were associated weakly with paternal antisocial behaviors. However, boys' delinquency scores increased steeply thereafter specifically for those who had fathers with higher antisocial symptoms. In addition, associations between delinquency and paternal antisociality were largest for boys with higher resting RSA. For girls, growth in delinquency was unrelated to both father antisociality and resting RSA. These findings (a) suggest moderating effects of children's age, sex, and PNS function on associations between father antisocial behavior and offspring delinquency; and (b) provide insights into differential vulnerability among children of fathers with ASPD.