Longitudinal relations between parenting stress and child internalizing and externalizing behaviors: Testing within-person changes, bidirectionality and mediating mechanisms

IntroductionParenthood can be experienced as a pleasant but challenging period for parents, possibly accompanied by parenting stress. Early parenthood in particular is a vulnerable period as many parents experience biological and psychosocial changes related to new parenthood. Previous studies have shown that parenting stress is related to child behavior problems, but few studies have investigated the transactional relations across time between parenting stress and child internalizing and externalizing outcomes separately, examining within-person changes. The first aim of this study was to examine the transactional within-person associations of parenting stress and child internalizing and externalizing behavior problems across childhood from age 9 months to 9 years. As a second aim, we examined parenting as a possible underlying mechanism of the transactional associations by testing whether parental warmth and hostility mediate within-person associations of parenting stress and child behavior across time.MethodData were analyzed from the Growing Up in Ireland longitudinal child cohort study including 7,208 caregiver-child dyads at wave 1 (child’s age 9 months), who were followed at child’s age three (wave 2), five (wave 3), and 9 years (wave 5). Primary caregiver’s and child’s age and gender, household income, occupational status, educational status, partner status, and cultural background were covariates assessed at all waves. Data were analyzed using a random intercept cross-lagged panel model (CLPM) in R-lavaan.ResultsBidirectional relations between parenting stress and child behavior were found for both internalizing and externalizing behavior from age 5 to 9, but not for earlier time points.DiscussionOur results did not indicate mediating effects of parental warmth or parental hostility in the associations between parenting stress and child behavior problems. Therefore, we conclude that parenting stress and child internalizing as well as parenting stress and child externalizing behaviors have transactional associations from child’s age 5 to 9 years. Future research examining transactional associations of parenting stress and child behaviors should investigate possible other mediations taking a within-person approach by utilizing the RI-CLPM

Fathers today: design of a randomized controlled trial examining the role of oxytocin and vasopressin in behavioral and neural responses to infant signals

BACKGROUND: Previous research has mostly focused on the hormonal, behavioral and neural correlates of maternal caregiving. We present a randomized, double-blind, placebo-controlled within-subject design to examine the effects of intranasal administration of oxytocin and vasopressin on parenting behavior and the neural and behavioral responses to infant cry sounds and infant threat. In addition, we will test whether effects of oxytocin and vasopressin administration are moderated by fathers' early childhood experiences. METHODS: Fifty-five first-time fathers of a child between two and seven months old will participate in three experimental sessions with intervening periods of one to two weeks. Participants self-administer oxytocin, vasopressin or a placebo. Infant-father interactions and protective parenting responses are observed during play. Functional Magnetic Resonance Imaging (fMRI) is used to examine the neural processing of infant cry sounds and infant threat. A handgrip dynamometer is used to measure use of handgrip force when listening to infant cry sounds. Participants report on their childhood experiences of parental love-withdrawal and abuse and neglect. DISCUSSION: The results of this study will provide important insights into the hormonal, behavioral and neural correlates of fathers' parenting behavior during the early phase of fatherhood. TRIAL REGISTRATION: Dutch Trial Register: NTR (ID: NL8124); Date registered: October 30, 2019

Meta-analysis of Genome-Wide Association Studies for Extraversion: Findings from the Genetics of Personality Consortium

Extraversion is a relatively stable and heritable personality trait associated with numerous psychosocial, lifestyle and health outcomes. Despite its substantial heritability, no genetic variants have been detected in previous genome-wide association (GWA) studies, which may be due to relatively small sample sizes of those studies. Here, we report on a large meta-analysis of GWA studies for extraversion in 63,030 subjects in 29 cohorts. Extraversion item data from multiple personality inventories were harmonized across inventories and cohorts. No genome-wide significant associations were found at the single nucleotide polymorphism (SNP) level but there was one significant hit at the gene level for a long non-coding RNA site (LOC101928162). Genome-wide complex trait analysis in two large cohorts showed that the additive variance explained by common SNPs was not significantly different from zero, but polygenic risk scores, weighted using linkage information, significantly predicted extraversion scores in an independent cohort. These results show that extraversion is a highly polygenic personality trait, with an architecture possibly different from other complex human traits, including other personality traits. Future studies are required to further determine which genetic variants, by what modes of gene action, constitute the heritable nature of extraversion

Heritability and genome-wide linkage scan of subjective happiness

Causes of individual differences in happiness, as assessed with the Subjective Happiness Scale, are investigated in a large of sample twins and siblings from the Netherlands Twin Register. Over 12,000 twins and siblings, average age 24.7 years (range 12 to 88), took part in the study. A genetic model with an age by sex design was fitted to the data with structural equation modeling in Mx. The heritability of happiness was estimated at 22% for males and 41% in females. No effect of age was observed. To identify the genomic regions contributing to this heritability, a genome-wide linkage study for happiness was conducted in sibling pairs. A subsample of 1157 offspring from 441 families was genotyped with an average of 371 micro-satellite markers per individual. Phenotype and genotype data were analyzed in MERLIN with multipoint variance component linkage analysis and age and sex as covariates. A linkage signal (logarithm of odds score 2.73, empirical p value 0.095) was obtained at the end of the long arm of chromosome 19 for marker D19S254 at 110 cM. A second suggestive linkage peak was found at the short arm of chromosome 1 (LOD of 2.37) at 153 cM, marker D1S534 (empirical p value of .209). These two regions of interest are not overlapping with the regions found for contrasting phenotypes (such as depression, which is negatively associated with happiness). Further linkage and future association studies are warranted

Genome-wide linkage scan for athlete status in 700 British female DZ twin pairs

Association studies, comparing elite athletes with sedentary controls, have reported a number of genes that may be related to athlete status. The present study reports the first genome wide linkage scan for athlete status. Subjects were 4488 adult female twins from the TwinsUK Adult Twin Registry (793 monozygotic [MZ] and 1000 dizygotic [DZ] complete twin pairs, and single twins). Athlete status was measured by asking the twins whether they had ever competed in sports and what was the highest level obtained. Twins who had competed at the county or national level were considered elite athletes. Using structural equation modeling in Mx, the heritability of athlete status was estimated at 66%. Seven hundred DZ twin pairs that were successfully genotyped for 1946 markers (736 microsatellites and 1210 SNPs) were included in the linkage analysis. Identical-by-descent probabilities were estimated in Merlin for a 1 cM grid, taking into account the linkage disequilibrium of correlated SNPs. The linkage scan was carried out in Mx using the π-approach. Suggestive linkages were found on chromosomes 3q22-q24 and 4q31-q34. Both areas converge with findings from previous studies using exercise phenotypes. The peak on 3q22-q24 was found at the SLC9A9 gene. The region 4q31-q34 overlaps with the region for which suggestive linkages were found in two previous linkage studies for physical fitness (FABP2 gene; Bouchard et al., 2000) and physical activity (UCP1 gene; Simonen et al., 2003). Future association studies should further clarify the possible role of these genes in athlete status

Genome-Wide Association Study of Exercise Behavior in Dutch and American Adults

The objective of this study was to identify genetic variants that are associated with adult leisure-time exercise behavior using genome-wide association in two independent samples

Meta-analysis of Genome-Wide Association Studies for Extraversion : Findings from the Genetics of Personality Consortium

Extraversion is a relatively stable and heritable personality trait associated with numerous psychosocial, lifestyle and health outcomes. Despite its substantial heritability, no genetic variants have been detected in previous genome-wide association (GWA) studies, which may be due to relatively small sample sizes of those studies. Here, we report on a large meta-analysis of GWA studies for extraversion in 63,030 subjects in 29 cohorts. Extraversion item data from multiple personality inventories were harmonized across inventories and cohorts. No genome-wide significant associations were found at the single nucleotide polymorphism (SNP) level but there was one significant hit at the gene level for a long non-coding RNA site (LOC101928162). Genome-wide complex trait analysis in two large cohorts showed that the additive variance explained by common SNPs was not significantly different from zero, but polygenic risk scores, weighted using linkage information, significantly predicted extraversion scores in an independent cohort. These results show that extraversion is a highly polygenic personality trait, with an architecture possibly different from other complex human traits, including other personality traits. Future studies are required to further determine which genetic variants, by what modes of gene action, constitute the heritable nature of extraversion.Peer reviewe

Thought Problems from Adolescence to Adulthood: Measurement Invariance and Longitudinal Heritability

This study investigates the longitudinal heritability in Thought Problems (TP) as measured with ten items from the Adult Self Report (ASR). There were ~9,000 twins, ~2,000 siblings and ~3,000 additional family members who participated in the study and who are registered at the Netherlands Twin Register. First an exploratory factor analysis was conducted to examine the underlying factor structure of the TP-scale. Then the TP-scale was tested for measurement invariance (MI) across age and sex. Next, genetic and environmental influences were modeled on the longitudinal development of TP across three age groups (12–18, 19–27 and 28–59 year olds) based on the twin and sibling relationships in the data. An exploratory factor analysis yielded a one-factor solution, and MI analyses indicated that the same TP-construct is assessed across age and sex. Two additive genetic components influenced TP across age: the first influencing TP throughout all age groups, while the second arises during young adulthood and stays significant throughout adulthood. The additive genetic components explained 37% of the variation across all age groups. The remaining variance (63%) was explained by unique environmental influences. The longitudinal phenotypic correlation between these age groups was entirely explained by the additive genetic components. We conclude that the TP-scale measures a single underlying construct across sex and different ages. These symptoms are significantly influenced by additive genetic factors from adolescence to late adulthood