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.

Neural correlates of face familiarity in institutionalised children and links to attachment disordered behaviour.

BACKGROUND: One of the most well-documented sequelae of early maltreatment and institutionalisation is attachment problems, including behaviours under the labels of reactive attachment disorder (RAD) and disinhibited social engagement disorder (DSED). Despite growing evidence of the neurobiological effects of institutionalisation, the neural correlates of these behavioural patterns are largely unknown. METHODS: The current study examined effects of both institutionalisation in general and attachment disordered behaviour, in particular, on brain-based markers of face processing, in 100 Portuguese children (70 currently institutionalised, 30 continuously raised by their families). Children's neural processing of caregiver's and stranger's faces was assessed with Event-Related Potentials (ERPs). RESULTS: Compared to children from the community, institutionalised children showed smaller amplitudes in the N170, to both stranger and caregiver faces. Amongst the institutionalised group, living in a setting with a higher children-to-caregivers' ratio was associated with smaller P400 amplitudes. The display of DSED symptoms was associated with a smaller P1 to both faces, as well as a reduced differentiation between faces in P400 amplitudes and smaller P400 to the stranger's face. In contrast, RAD symptoms were not associated with any ERP measures. CONCLUSIONS: Results replicate previously reported hypoactivation in institutionalised children, in a less-globally deprived setting than past work, indicating that such a pattern is associated with lack of individualised care and increased symptoms of DSED.

Parental history of positive development and child behavior in next generation offspring: A two-cohort prospective intergenerational study.

This study examined whether positive development (PD) in adolescence and young adulthood predicts offspring behavior in two Australasian intergenerational cohorts. The Australian Temperament Project Generation 3 Study assessed PD at age 19-28 (years 2002-2010) and behavior in 1165 infants (12-18 months; 608 girls) of 694 Australian-born parents (age 29-35; 2012-2019; 399 mothers). The Dunedin Multidisciplinary Health and Development Parenting Study assessed PD at age 15-18 (years 1987-1991) and behavior in 695 preschoolers (3-5 years; 349 girls) and their New Zealand born parents (age 21-46; 1994-2018; 363 mothers; 89% European ethnicity). In both cohorts, PD before parenthood predicted more positive offspring behavior (ßrange  = .11-.16) and fewer behavior problems (ßrange  = -.09 to -.11). Promoting strengths may secure a healthy start to life.

Beyond orchids and dandelions: Susceptibility to environmental influences is not bimodal.

This study focused on generality versus specificity of susceptibility of effects of eight family and child-care exposures measured between 3 and 54 months of age (e.g., sensitive parenting, child-care quality) on five child development outcomes assessed at age 4.5 years (e.g. behavior problems, preacademic skill), using data from The National Institute of Child Health and Human Development (NICHD) Study of Early Child Care and Youth Development (n = 1,364, boys = 705; White = 1,097, Black = 176, other = 91), while applying a novel influence-statistics method. Results indicated that susceptibility across the environment-predictor:child-outcome associations is normally rather than bimodally (i.e., orchid-dandelion) distributed. Analysis of susceptibility documents both domain generality and specificity of developmental plasticity, with effect sizes proving small in the former case. As predicted, children who as infants had difficult temperaments or who scored higher on a polygenic-plasticity score (serotonin-transporter-linked promoter region [5-HTTLPR], dopamine receptor D4 [DRD4], brain-derived neurotrophic factor [BDNF]) proved somewhat more susceptible to some of the environmental effects investigated. Results lead to the recommendation that two-types-of-individuals vis-a-vis susceptibility to environmental influences be questioned and general-trait conceptions of susceptibility be further investigated.

Indirect effects, via parental factors, of income harshness and unpredictability on kindergarteners' socioemotional functioning.

Drawing on data from the Early Childhood Longitudinal Study-Birth Cohort (n = 10,700), we evaluate indirect effects - via parent negative psychology and harsh-inconsistent parenting - of income harshness, unpredictability, and their interaction on kindergarteners' socioemotional development. Income harshness is operationalized as the typical level of family income-to-needs across four repeated measurements from 9 months to kindergarten and unpredictability as random variation across the same repeated measurements. Results indicate that the effects of greater income harshness and the harshness-X-unpredictability interaction (reflecting more predictable income harshness) on more "problematic" child behavior operated via both parent negative psychology (i.e., greater psychological stress) and harsh-inconsistent parenting. Results underscore the utility of simultaneously investigating effects of income harshness and unpredictability, as well as their interaction and mechanisms of influence.

Three phases of Gene × Environment interaction research: Theoretical assumptions underlying gene selection.

Some Gene × Environment interaction (G×E) research has focused upon single candidate genes, whereas other related work has targeted multiple genes (e.g., polygenic scores). Each approach has informed efforts to identify individuals who are either especially vulnerable to the negative effects of contextual adversity (diathesis stress) or especially susceptible to both positive and negative contextual conditions (differential susceptibility). A critical step in all such molecular G×E research is the selection of genetic variants thought to moderate environmental influences, a subject that has not received a great deal of attention in critiques of G×E research (beyond the observation of small effects of individual genes). Here we conceptually distinguish three phases of G×E work based on the selection of genes presumed to moderate environmental effects and the theoretical basis of such decisions: (a) single candidate genes, (b) composited (multiple) candidate genes, and (c) GWAS-derived polygenic scores. This illustrative, not exhaustive, review makes it clear that implicit or explicit theoretical assumptions inform gene selection in ways that have not been clearly articulated or fully appreciated.

Differential susceptibility 2.0: Are the same children affected by different experiences and exposures?

Differential susceptibility theory stipulates that some children are more susceptible than others to both supportive and adverse developmental experiences/exposures. What remains unclear is whether the same individuals are most affected by different exposures (i.e., domain general vs. specific). We address this issue empirically for the first time using, for illustrative and proof-of-principle purposes, a novel influence-statistics' method with data from the National Institute of Child Health and Human Development (NICHD) Study of Early Child Care. Results indicated that previously documented effects of greater quality of care on enhanced pre-academic skills and greater quantity of care on more behavior problems apply mostly to different children. Analyses validating the new method indicated, as predicted, that (a) the quantity-of-care effect applied principally to children from more socioeconomically advantaged families and that (b) being highly susceptible to both, one or neither childcare effect varied as a function of a three-gene, polygenic-plasticity score (serotonin transporter linked polymorphic region [5-HTTLPR], dopamine receptor D4 [DRD4], brain-derived neurotrophic factor [BDNF]) in a dose-response manner (i.e., 2>1>0). While domain-specific findings involving child-care effects cannot be generalized to other environmental influences, the influence-statistics' approach appears well suited for investigating the generality-specificity of environment effects, that is, of "differential, differential susceptibility."

Infant temperament, early-childhood parenting, and early-adolescent development: Testing alternative models of Parenting × Temperament interaction.

Here we evaluate whether infant difficult temperament (6 months) functions as a vulnerability or more general plasticity factor when investigating effects of early-childhood parenting (8-42 months) on both positive and negative early-adolescent socioemotional development (age 8-11 years). Using data from the Avon Longitudinal Study of Parents and Children (ALSPAC, N = 14,541) and a re-parameterized model-testing approach to distinguish alternative person × environment conceptual models, results indicated that temperament × parenting interacted in predicting externalizing (i.e., hyperactivity, conduct problems), but not other behavior (i.e., emotional symptoms, peer problems), in a (weak) differential susceptibility manner. While more and less supportive parenting predicted, respectively, fewer and more behavior problems, it did so more strongly for children who were more difficult as infants.

Testing the empirical integration of threat-deprivation and harshness-unpredictability dimensional models of adversity.

Recent dimensional models of adversity informed by a neurobiological deficit framework highlights threat and deprivation as core dimensions, whereas models informed by an evolutionary, adaptational and functional framework calls attention to harshness and unpredictability. This report seeks to evaluate an integrative model of threat, deprivation, and unpredictability, drawing on the Fragile Families Study. Confirmatory factor analysis of presumed multiple indicators of each construct reveals an adequate three-factor structure of adversity. Theory-based targeted predictions of the developmental sequelae of each dimension also received empirical support, with deprivation linked to health problems and cognitive ability; threat linked to aggression; and unpredictability to substance use and sexual risk-taking. These findings lend credibility to utility of the three-dimensional integrative framework of adversity. It could thus inform development of dimensional measures of risk assessment and exploration of multidimensional adversity profiles, sensitive to individual differences in lived experiences, supporting patient-centered, strength-based approaches to services.

Why and how does early adversity influence development? Toward an integrated model of dimensions of environmental experience.

Two extant frameworks - the harshness-unpredictability model and the threat-deprivation model - attempt to explain which dimensions of adversity have distinct influences on development. These models address, respectively, why, based on a history of natural selection, development operates the way it does across a range of environmental contexts, and how the neural mechanisms that underlie plasticity and learning in response to environmental experiences influence brain development. Building on these frameworks, we advance an integrated model of dimensions of environmental experience, focusing on threat-based forms of harshness, deprivation-based forms of harshness, and environmental unpredictability. This integrated model makes clear that the why and the how of development are inextricable and, together, essential to understanding which dimensions of the environment matter. Core integrative concepts include the directedness of learning, multiple levels of developmental adaptation to the environment, and tradeoffs between adaptive and maladaptive developmental responses to adversity. The integrated model proposes that proximal and distal cues to threat-based and deprivation-based forms of harshness, as well as unpredictability in those cues, calibrate development to both immediate rearing environments and broader ecological contexts, current and future. We highlight actionable directions for research needed to investigate the integrated model and advance understanding of dimensions of environmental experience.

Environmental harshness and unpredictability: Do they affect the same parents and children?

Differential susceptibility theory stipulates that individuals vary in their susceptibility to environmental effects, often implying that the same individuals differ in the same way in their susceptibility to different environmental exposures. The latter point is addressed herein by evaluating the extent to which early-life harshness and unpredictability affect mother's psychological well-being and parenting, as well as their adolescent's life-history strategy, as reflected in number of sexual partners by age 15 years, drawing on data from the National Institute of Child Health and Human Development (NICHD) Study of Early Child Care and Youth Development. Results indicated that mothers whose well-being and parenting proved more susceptible to harshness also proved somewhat more susceptible to environmental unpredictability, with the same being true of adolescent sexual behavior. Nevertheless, findings caution against overgeneralizing sample-level findings to all individuals.

Childhood sexual abuse and pervasive problems across multiple life domains: Findings from a five-decade study.

The aim of this study was to use longitudinal population-based data to examine the associations between childhood sexual abuse (CSA) and risk for adverse outcomes in multiple life domains across adulthood. In 937 individuals followed from birth to age 45y, we assessed associations between CSA (retrospectively reported at age 26y) and the experience of 22 adverse outcomes in seven domains (physical, mental, sexual, interpersonal, economic, antisocial, multi-domain) from young adulthood to midlife (26 to 45y). Analyses controlled for sex, socioeconomic status, prospectively reported child harm and household dysfunction adverse childhood experiences, and adult sexual assault, and considered different definitions of CSA. After adjusting for confounders, CSA survivors were more likely than their peers to experience internalizing, externalizing, and thought disorders, suicide attempts, health risk behaviors, systemic inflammation, poor oral health, sexually transmitted diseases, high-conflict relationships, benefit use, financial difficulties, antisocial behavior, and cumulative problems across multiple domains in adulthood. In sum, CSA was associated with multiple persistent problems across adulthood, even after adjusting for confounding life stressors, and the risk for particular problems incremented with CSA severity. The higher risk for most specific problems was small to moderate, but the cumulative long-term effects across multiple domains reflect considerable individual and societal burden.

Parenting, Peers and Psychosocial Adjustment: Are the Same-or Different-Children Affected by Each?

The prospective research presented herein extends work on parent and peer effects on adolescent psychosocial adjustment by looking beyond average effects. Instead, it considers variation in susceptibility to each source of influence in order to assess the extent to which those individuals most and least susceptible to parent effects are similarly-or differentially-susceptible to peer effects. Data from the NICHD Study of Early Child Care and Youth Development (n = 1364, 48.3% female, age range: 10-15 yrs., race/ethnicity: 80.4% white, 12.9% black and 6.7% other) was analyzed to assess the degree to which each child was susceptible to parent and peer effects. Toward this end, an influence statistic, DFBETAS, was used. A significant and moderate positive association between the two susceptibility effects indicated that children most or least susceptible to the effects of quality of parenting proved to be similarly affected by their peers, although this was not the case for a substantial minority of youth. The fact that at least some children vary dramatically in the effects to which they are most susceptible is discussed with respect to potential targets of intervention, namely, parents or peers.

Early life adversity, pubertal timing, and epigenetic age acceleration in adulthood.

BACKGROUND: Given associations linking early life adversity, pubertal timing, and biological aging, we examined the direct and indirect effects of early life trauma on adult biological aging (via age of menarche). METHODS: Participants were premenopausal women (N = 183). Path models evaluated whether early life trauma predicted early pubertal timing and thereby, adult epigenetic age acceleration (indexed via four epigenetic clocks: Horvath DNAm Age, Hannum DNAm Age, DNAm PhenoAge, and DNAm GrimAge). Secondary analyses explored the effects of type of trauma (abuse and neglect) and adult chronic stress status (caregiver of child with autism and non-caregiver). RESULTS: Early life trauma and earlier age at menarche independently predicted accelerated aging based on one of the four epigenetic clocks, DNAm GrimAge, though early life trauma was not associated with age of menarche. Childhood abuse, but not neglect, predicted faster epigenetic aging; results did not differ by chronic stress status. CONCLUSIONS: Early trauma and early menarche appear to exert independent effects on DNAm GrimAge, which has been shown to be the strongest epigenetic predictor of mortality risk. This study identifies a potential correlate or determinant of accelerated epigenetic aging-menarcheal age. Future research should address the limitations of this study by using racially diverse samples.

The co-occurrence between symptoms of internet gaming disorder and psychiatric disorders in childhood and adolescence: prospective relations or common causes?

BACKGROUND: Internet gaming disorder (IGD) is highlighted as a condition for further study in the Diagnostic and Statistical Manual of Mental Disorders Fifth Edition (DSM-5). Some studies indicate that IGD appears comorbid with other psychiatric disorders. We examine concurrent and prospective links between symptoms of IGD and symptoms of common psychiatric disorders in childhood and adolescence to determine whether observed comorbidity is a result of (a) reciprocal relations or (b) common underlying causes. METHODS: A community sample (n = 702) of Norwegian children completed the Internet Gaming Disorder Interview (IGDI) to assess DSM-5 defined IGD symptoms at ages 10, 12 and 14 years. The Child and Adolescent Psychiatric Assessment (CAPA) assessed symptoms of depression, anxiety, attention-deficit hyperactivity disorder (ADHD), oppositional defiant disorder (ODD) and conduct disorder (CD) at the same time points. RESULTS: A Random Intercept Cross-lagged Panel Model (RI-CLPM), which captures pure within-person changes and adjusts for all unmeasured time-invariant factors (e.g., genetics, parent education) revealed no associations between IGD symptoms and psychopathology, except that increased IGD symptoms at ages 10 and 12 predicted decreased symptoms of anxiety two years later. CONCLUSIONS: No support emerged for concurrent or prospective relations between IGD and psychiatric symptoms, except in one case: increased IGD symptoms forecasted reduction in anxiety symptoms. Observed co-occurrence between IGD symptoms and mental health problems can mainly be attributed to common underlying factors.

Time Spent Gaming and Social Competence in Children: Reciprocal Effects Across Childhood.

Electronic games are popular and many children spend much time on this activity. Here we investigate whether the quantity of time children spend on gaming is related to their social development, making this the first study to examine this relationship in children. We examine prospective relations between time spent gaming and social competence in a community sample of Norwegian 6 year olds (n = 873) followed up at ages 8, 10, and 12, controlling for socioeconomic status, body mass index, and time spent gaming together with friends. Results revealed that greater social competence at both 8 and 10 years predicted less gaming 2 years later and that more age-10 gaming predicted less social competence at age 12 but only among girls.

Distinguishing differential susceptibility, diathesis-stress, and vantage sensitivity: Beyond the single gene and environment model.

Currently, two main approaches exist to distinguish differential susceptibility from diathesis-stress and vantage sensitivity in Genotype × Environment interaction (G × E) research: regions of significance (RoS) and competitive-confirmatory approaches. Each is limited by its single-gene/single-environment foci given that most phenotypes are the product of multiple interacting genetic and environmental factors. We thus addressed these two concerns in a recently developed R package (LEGIT) for constructing G × E interaction models with latent genetic and environmental scores using alternating optimization. Herein we test, by means of computer simulation, diverse G × E models in the context of both single and multiple genes and environments. Results indicate that the RoS and competitive-confirmatory approaches were highly accurate when the sample size was large, whereas the latter performed better in small samples and for small effect sizes. The competitive-confirmatory approach generally had good accuracy (a) when effect size was moderate and N ≥ 500 and (b) when effect size was large and N ≥ 250, whereas RoS performed poorly. Computational tools to determine the type of G × E of multiple genes and environments are provided as extensions in our LEGIT R package.

Mothers' distress exposure and children's withdrawn behavior - A moderating role for the Interferon Gamma gene (IFNG).

The dysregulation of the inflammatory response, including pro-inflammatory molecules, produces neuropsychiatric symptoms and depression-like behavior, including withdrawal from the physical and social environment. Genetic variants that enhance immune reactivity may thus increase inflammatory and withdrawn reactions to stress. Here we investigated a functional polymorphism of Interferon Gamma gene (IFNG +874 T > A, rs2430561) as moderator of the relationship between mothers' distress exposure and children's withdrawn behavior at preschool age. Participants were 198 Portuguese preschool children (mean age = 57.98 months). Exposure to mother's distress was assessed using the Brief Symptom Inventory, and withdrawn behavior with the Caregiver Teacher Report Form. All children provided saliva samples for genotyping. Contrary to expecations based on prior work, the rs2430561 AA genotype-not the T variant-interacted with (high levels of) mothers' distress exposure, to increase children's withdrawn behavior. No significant main effects were detected. The polymorphism in Interferon Gamma gene showed specific environmental stressor-dependent effects on withdrawn behavior during childhood, ones which are interpreted in light of the "behavioral immune system" hypothesis, and which proved inconsistent with diathesis-stress thinking.

General Psychopathology and Dysregulation Profile in a Longitudinal Community Sample: Stability, Antecedents and Outcomes.

The general factor of psychopathology (GP, or p factor) and the Dysregulation Profile (DP) are two conceptually similar, but independently developed approaches to understand psychopathology. GP and DP models and their stability, antecedents and outcomes are studied in a longitudinal sample of 1073 children (49.8% female). GP and DP models were estimated at ages 8 and 14 years using the parent-reported Child Behavior Checklist (CBCL) and Youth Self Report (YSR). Early childhood antecedents and adolescent outcomes were derived using a multi-method multi-informant approach. Results showed that the general GP and DP had similar key symptoms and were similarly related to early-childhood antecedents (e.g., lower effortful control, higher maternal depression) and adolescent outcomes (e.g., reduced academic functioning, poorer mental health). This study demonstrates that GP and DP are highly similar constructs in middle childhood and adolescence, both describing a general vulnerability for psychopathology with (emotional) dysregulation at its core. Scientific integration of these approaches could lead to a better understanding of the structure, antecedents and outcomes of psychopathology.

Polygenic differential susceptibility to prenatal adversity.

A recent article in this journal reported a number of gene × environment interactions involving a serotonin transporter-gene network polygenic score and a composite index of prenatal adversity predicting several problem behavior outcomes at 48 months (e.g., anxious/depressed, pervasive developmental problems) and at 60 months (e.g., withdrawal, internalizing problems), yet did not illuminate the nature or form these genetic × environment interactions took. Here we report results of six additional analyses to evaluate whether these interactions reflected diathesis-stress or differential-susceptibility related processes. Analyses of the regions of significance and proportion of interaction index are consistent with the diathesis-stress model, seemingly because of the truncated nature of the adversity score (which did not extend to supportive/positive prenatal experiences/exposures); in contrast, the proportion (of cases) affected index favors the differential-susceptibility model. These results suggest the need for future studies to extend measurement of the prenatal environment to highly supportive experiences and exposures.