This study investigated the psychometric properties of the Highly Sensitive Child-Rating System (HSC-RS), the existence of sensitivity groups, and the characterization of sensitivity at behavioral, genetic, and physiological levels in 541 preschoolers (M(SD)age = 3.56(0.27); 45%male; 87%Caucasian). Temperament, genetic, cortisol, and electroencephalography asymmetry data were collected in subsamples (n = 94-476). Results showed a reliable observational measure of sensitivity. Confirmatory factor and latent class analysis supported a one-factor solution and three sensitivity groups, that are a low (23.3%), medium (54.2%), and a high (22.5%) sensitivity group. Hierarchical regression analyses showed moderate associations between HSC-RS and observed temperament traits (i.e., behavioral level). In addition, a small negative association between HSC-RS and a genome-wide association study polygenic risk score (GWAS PGS) for Attention Deficit Hyperactivity Disorder was found. No relations with candidate genes, other GWAS PGS phenotypes, and physiological measures were found. Implications of our findings and possible explanations for a lack of these associations are discussed.

The field of developmental psychopathology has made significant contributions to our understanding of both typical and atypical development. However, while there are established theories for developmental psychopathology with detailed criteria for pathological outcomes, there is less agreement regarding development under optimal conditions and the definition of positive outcomes. In this conceptual paper, I make the case that a better understanding of positive child development is crucial because it will not only advance our general knowledge on human development but also complement current work on developmental psychopathology. After defining positive development as the development of positive functioning in children, such as skills, strengths, competencies, and wellbeing, rather than the absence of problems, current concepts with relevance for positive development are reviewed, before highlighting gaps in our knowledge on positive development and suggestions for future research. Although several of the reviewed frameworks provide important contributions to the conceptualization of positive development, most of them focus on positive functioning in adults with limited consideration of development in the early years. More research is needed that specifically targets the development of positive outcomes from early childhood onward in order to develop a more comprehensive and holistic theory of positive child development.

Children differ substantially in their sensitivity to the quality of their environment. Some are more sensitive and more likely to develop Post-Traumatic Stress Disorder (PTSD) in response to Childhood Adversities (CAs), but might also benefit more from Positive Home Experiences (PHE). The aim of this study is to investigate the role of Environmental Sensitivity (ES), CAs and PHEs in PTSD development in children and adolescents. Data was collected from N = 2,569 children/adolescents. PTSD symptoms, CAs, PHEs and ES were assessed with self-report measures. We found that higher ES and CAs emerged as risk factors for PTSD development whereas higher levels of PHEs protected against PTSD. ES moderated the effects of CAs (β = 1.08, p < .001) on PTSD symptoms in the total sample. This moderating effect was more pronounced in girls, suggesting that highly sensitive girls with high childhood adversities were more likely to have higher PTSD symptoms than girls with low levels of sensitivity (β = 1.09, p < .001). In conclusion, Environmental Sensitivity played an important role as a risk factor for PTSD and as a moderating factor that accentuated the main effects of childhood adversities, particularly in girls.

Refugee children are often exposed to substantial trauma, placing them at increased risk for mental illness. However, this risk can be mitigated by a capacity for resilience, conferred from multiple ecological systems (e.g., family, community), including at an individual biological level. We examined the ability of hair cortisol concentrations and polygenic scores for mental health to predict risk and resilience in a sample of Syrian refugee children (n = 1359). Children were categorized as either at-risk or resilient depending on clinical thresholds for posttraumatic stress disorder, depression, and externalizing behavior problems. Logistic regression was used to examine main and interacting effects while controlling for covariates. Elevated hair cortisol concentrations were significantly associated with reduced resilience (odds ratio (OR)=0.58, 95%CI [0.40, 0.83]) while controlling for levels of war exposure. Polygenic scores for depression, self-harm, and neuroticism were not found to have any significant main effects. However, a significant interaction emerged between hair cortisol and polygenic scores for depression (OR=0.04, 95%CI [0.003 0.47]), suggesting that children predisposed to depression were more at risk for mental health problems when hair cortisol concentrations were high. Our results suggest that biomarkers (separately and in combination) might support early identification of refugee children at risk for mental health problems.

Children differ in their environmental sensitivity (ES), which can be measured observationally or by self-report questionnaire. A parent-report scale represents an important tool for investigating ES in younger children but has to be psychometrically robust and valid. In the current multistudy, we validated the parent-report version of the Highly Sensitive Child (HSC-PR) scale in Italian children, evaluating its factorial structure (Study 1, N = 1,857, 6.2 years, age range: 2.6–14 years) through a multigroup Confirmatory Factory Analysis in preschoolers (n = 1,066, 4.2 years) and school-age children (n = 791, 8.8 years). We then investigated the HSC-PR relationship with established temperament traits (Study 2, N = 327, 4.3 years), before exploring whether the scale moderates the effects of parenting stress on children’s emotion regulation (Study 3, N = 112, 6.5 years). We found support for a bi-factor structure in both groups, though in preschoolers minor adaptations were suggested for one item. Importantly, the HSC-PR did not fully overlap with common temperament traits and moderated the effects of parenting stress on children emotion regulation. To conclude, the HSC-PR performs well and appears to capture ES in children.

The interplay of parenting and environmental sensitivity on children’s behavioral adjustment during, and immediately after, the COVID-19 lockdown restrictions was investigated in two longitudinal studies involving Italian preschoolers (Study 1, N = 72; 43% girls, Myears = 3.82(1.38)) and primary school children (Study 2, N = 94; 55% girls, Myears = 9.08(0.56)). Data were collected before and during the first-wave lockdown (Studies 1 and 2) and one month later (Study 1). Parental stress and parent–child closeness were measured. Markers of environmental sensitivity in children were temperamental fearfulness and Sensory Processing Sensitivity. Results showed little change in externalizing and internalizing behaviors over time, but differences emerged when considering parenting and children’s environmental sensitivity. In preschoolers, greater parenting stress was related to a stronger increase in internalizing and externalizing behaviors, with children high in fearful temperament showing a more marked decrease in externalizing behaviors when parenting stress was low. In school-aged children, parent–child closeness emerged as a protective factor for internalizing and externalizing behaviors during COVID-19, with children high in Sensory Processing Sensitivity showing a marked decrease in internalizing behaviors when closeness was high. Implications for developmental theory and practice in times of pandemic are discussed.

Children differ in their response to environmental exposures, with some being more sensitive to contextual factors than others. According to theory, such variability is the result of individual differences in neurobiological sensitivity to environmental features, with some individuals generally more affected by both negative and/or positive experiences. In this exploratory study we tested whether left and right amygdala and hippocampus volumes (corrected for total brain size) account for individual differences in response to environmental influences in a sample of 62 boys. Cumulative general environmental quality, ranging from low to high, was measured across the first 9 years and child behavior was reported by teachers when boys were 12–13 years old. According to analyses, only the left amygdala volume – not any of the other brain volumes – emerged as an important brain region for sensitivity to positive environmental aspects. Boys with a larger left amygdala benefited significantly more from higher environmental quality than boys with a smaller left amygdala whilst not being more vulnerable to lower quality. Besides providing preliminary evidence for differences in environmental sensitivity due to brain structure, the results also point to the left amygdala as having a specific role regarding the response to environmental influences.

Rigorously evaluated interventions that target protective factors and positive resources rather than ameliorating negative outcomes in child refugees are rare. To address this, we developed and evaluated a short, group-based resilience-building intervention called Strengths for the Journey (SFJ), which was designed for war-affected children. We conducted a quasi-randomized pilot study of the SFJ intervention with 72 7- to 14-year-old forcibly displaced children (Mage = 10.76, 64.8% female) in three refugee camps in Lesvos, Greece. Intervention effectiveness was assessed by measuring pre-post changes in well-being, self-esteem, optimism, and depressive symptoms from before (T1) to immediately after the intervention/wait-list task (T2). Four focus group interviews were conducted with 31 of the participants to discuss their views on the effects of the intervention and the continued use of the skills that were learned. Using repeated-measures ANOVAs, we found improvements in well-being, F (1, 46) = 42.99, ηp2 = .48, self-esteem, F (1, 56) = 29.11, ηp2 = .40, optimism, F (1, 53) = 27.16, ηp2 = .34, and depressive symptoms, F (1, 31) = 62.14, ηp2 = .67, in the intervention group compared with the wait-listed group (p < .05). Focus group participants highlighted the importance of SFJ in developing a sense of togetherness and building their strengths. Child refugees in low-resource settings may benefit from brief, first-line interventions that target protective factors such as well-being, hope, self-esteem, and belonging.

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.

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.

The quality of prenatal maternal mental health, from psychological stress and depressive symptoms to anxiety and other nonpsychotic mental disorders, profoundly affects fetal neurodevelopment. Despite the evidence for the influence of positive mental well-being on health, there is, to our knowledge, no research examining the possible effects of positive antenatal mental health on the development of the offspring. Using exploratory bifactor analysis, this prospective study (n = 1,066) demonstrated the feasibility of using common psychiatric screening tools to examine the effect of positive maternal mental health. Antenatal mental health was assessed during 26th week of pregnancy. The effects on offspring were assessed when the child was 12, 18, and 24 months old. Results showed that positive antenatal mental health was uniquely associated with the offspring's cognitive, language and parentally rated competences. This study shows that the effects of positive maternal mental health are likely to be specific and distinct from the sheer absence of symptoms of depression or anxiety.

While environmental adversity has been shown to increase risk for psychopathology, individuals differ in their sensitivity to these effects. Both genes and childhood experiences are thought to influence sensitivity to the environment, and these factors may operate synergistically such that the effects of childhood experiences on later sensitivity are greater in individuals who are more genetically sensitive. In line with this hypothesis, several recent studies have reported a significant three-way interaction (Gene × Environment × Environment) between two candidate genes and childhood and adult environment on adult psychopathology. We aimed to replicate and extend these findings in a large, prospective multiwave longitudinal study using a polygenic score of environmental sensitivity and objectively measured childhood and adult material environmental quality. We found evidence for both Environment × Environment and Gene × Environment × Environment effects on psychological distress. Children with a poor-quality material environment were more sensitive to the negative effects of a poor environment as adults, reporting significantly higher psychological distress scores. These effects were further moderated by a polygenic score of environmental sensitivity. Genetically sensitive children were more vulnerable to adversity as adults, if they had experienced a poor childhood environment but were significantly less vulnerable if their childhood environment was positive. These findings are in line with the differential susceptibility hypothesis and suggest that a life course approach is necessary to elucidate the role of Gene × Environment in the development of mental illnesses.

While many studies focus on the association between early life adversity and the later risk for psychopathology, few simultaneously explore diverse forms of environmental adversity. Moreover, those studies that examined the cumulative impact of early life adversity focus uniquely on postnatal influences. The objective of this study was to focus on the fetal period of development to construct and validate a cumulative prenatal adversity score in relation to a wide range of neurodevelopmental outcomes. We also examined the interaction of this adversity score with a biologically informed genetic score based on the serotonin transporter gene. Prenatal adversities were computed in two community birth cohorts using information on health during pregnancy, birth weight, gestational age, income, domestic violence/sexual abuse, marital strain, as well as maternal smoking, anxiety, and depression. A genetic score based on genes coexpressed with the serotonin transporter in the amygdala, hippocampus, and prefrontal cortex during prenatal life was constructed with an emphasis on functionally relevant single nucleotide polymorphisms, that is, expression quantitative trait loci. Prenatal adversities predicted a wide range of developmental and behavioral alterations in children as young as 2 years of age in both cohorts. There were interactions between the genetic score and adversities for several domains of the Child Behavior Checklist (CBCL), with pervasive developmental problems remaining significant adjustment for multiple comparisons. Scores combining different prenatal adverse exposures predict childhood behavior and interact with the genetic background to influence the risk for psychopathology.

Here we tested whether there was genetic moderation of effects of early maternal sensitivity on social–emotional and cognitive–linguistic development from early childhood onward and whether any detected Gene × Environment interaction effects proved consistent with differential-susceptibility or diathesis–stress models of Person × Environment interaction (N = 695). Two new approaches for evaluating models were employed with 12 candidate genes. Whereas maternal sensitivity proved to be a consistent predictor of child functioning across the primary-school years, candidate genes did not show many main effects, nor did they tend to interact with maternal sensitivity/insensitivity. These findings suggest that the developmental benefits of early sensitive mothering and the costs of insensitive mothering look more similar than different across genetically different children in the current sample. Although acknowledgement of this result is important, it is equally important that the generally null Gene × Environment results reported here not be overgeneralized to other samples, other predictors, other outcomes, and other candidate genes.

We provide a theoretical and empirical basis for the claim that individual differences exist in developmental plasticity and that phenotypic plasticity should be a subject of study in its own right. To advance this argument, we begin by highlighting challenges that evolutionary thinking poses for a science of development and psychopathology, including for the diathesis–stress framework that has (fruitfully) guided so much empirical inquiry on developmental risk, resilience, and dysregulation. With this foundation laid, we raise a series of issues that the differential-susceptibility hypothesis calls attention to, while highlighting findings that have emerged over just the past several years and are pertinent to some of the questions posed. Even though it is clear that this new perspective on Person × Environment interaction is stimulating research and influencing how hypotheses are framed and data interpreted, a great many topics remain that need empirical attention. Our intention is to encourage students of development and psychopathology to treat phenotypic plasticity as an individual-difference construct while exploring unknowns in the differential-susceptibility equation.

Evidence indicates that maternal prenatal distress predicts problematic health and behavioral outcomes in children as well as infant/child cortisol levels and negative emotionality as reviewed here. Evidence that these physiological and behavioral characteristics themselves moderate environmental effects on development in a “for better and for worse” manner consistent with Belsky's differential susceptibility hypothesis and Boyce and Ellis' notions of biological sensitivity to context raises the prospect that susceptibility to rearing is a function of nurture (i.e., fetal environment), consistent with Boyce and Ellis' proposal that plasticity can be shaped by developmental experience. This hypothesis is supported by new findings from the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development showing that low birth weight, a marker for an adverse prenatal environment, predicts infant difficult temperament, which is a susceptibility factor that we previously showed as moderating, in a for better and for worse manner, the effects of parenting and child care quality on socioemotional functioning. Moreover, recent Gene × Environment interaction research raises the prospect that some fetuses may be more susceptible to such “prenatal programming of postnatal plasticity” as a result of their genetic makeup. If this proves true, it will be consistent with the conclusion that early developmental plasticity is a function of both nature and nurture and may be evolutionarily adaptive, a further possibility considered in the discussion.