Misaki N. Natsuaki

The Early Growth and Development Study: A Prospective Adoption Study From Birth Through Middle Childhood

The Early Growth and Development Study is a prospective adoption study of birth parents, adoptive parents, and adopted children recruited in two cohorts (N = 561 triads). The primary study aims are to examine how family, peer, and contextual processes affect childrens adjustment, and to examine their interplay (mediation, moderation) with genetic influences. Participants were recruited through adoption agencies located throughout the United States following the birth of a child. Assessments are ongoing, in 9-month intervals until the child reaches 3 years of age and in 1-year intervals thereafter through age 9. Data collection includes the following primary constructs: child temperament, social behavior, school performance, mental health, and health; birth and adoptive parent personality characteristics, mental health, competence, stress, health, context, substance use, parenting, and marital relations; and pregnancy use of drugs and maternal stress during pregnancy. DNA and salivary cortisol samples have also been collected. Analyses have indicated evidence for genotype-environment interactions during early childhood. Study procedures, sample representativeness (including tests of potential confounds in the adoption design), and an overview of findings to date are summarized, and future plans are described.

The longitudinal effects of stressful life events on adolescent depression are buffered by parent–child closeness

This study investigated the prospective links of negative life events and parent-child closeness with depressive symptoms among siblings using a multilevel modeling approach with a genetically informative design. The sample consisted of 756 adolescents (378 sibling pairs) who participated in two waves of the Nonshared Environment in Adolescent Development Project. Sibling pairs with varying degree of genetic relatedness (i.e., monozygotic, dizygotic, full siblings, half siblings, and genetically unrelated siblings) were included. The results showed that negative life events, both personal and family life events, and parent-child closeness at Time 1 were significantly associated with depressive symptoms at Time 2 after accounting for the intrapair correlations between siblings. The effects remained significant after controlling for the levels of preexisting depressive symptoms. More importantly, closeness with mothers, but not with fathers, moderated the effects of both personal and family negative life events on subsequent depressive symptoms.

The nature of nurture: disentangling passive genotype-environment correlation from family relationship influences on children's externalizing problems

The relationship between interparental conflict, hostile parenting, and childrens externalizing problems is well established. Few studies, however, have examined the pattern of association underlying this constellation of family and child level variables while controlling for the possible confounding presence of passive genotype–environment correlation. Using the attributes of 2 genetically sensitive research designs, the present study examined associations among interparental conflict, parent-to-child hostility, and childrens externalizing problems among genetically related and genetically unrelated mother–child and father–child groupings. Analyses were conducted separately by parent gender, thereby allowing examination of the relative role of the mother–child and father–child relationships on childrens behavioral outcomes. Path analyses revealed that for both genetically related and genetically unrelated parents and children, indirect associations were apparent from interparental conflict to child externalizing problems through mother-to-child and father-to-child hostility. Associations between interparental conflict and parent-to-child hostility across genetically related and genetically unrelated parent–child groupings were significantly stronger for fathers compared to mothers. Results are discussed with respect to the role of passive genotype–environment correlation as a possible confounding influence in interpreting research findings from previous studies conducted in this area. Implications for intervention programs focusing on family process influences on child externalizing problems are also considered.

Using an Adoption Design to Separate Genetic, Prenatal, and Temperament Influences on Toddler Executive Function

Poor executive functioning has been implicated in childrens concurrent and future behavioral difficulties, making work aimed at understanding processes related to the development of early executive function (EF) critical for models of developmental psychopathology. Deficits in EF have been associated with adverse prenatal experiences, genetic influences, and temperament characteristics. However, our ability to disentangle the predictive and independent effects of these influences has been limited by a dearth of genetically informed research designs that also consider prenatal influences. The present study examined EF and language development in a sample of 361 toddlers who were adopted at birth and reared in nonrelative adoptive families. Predictors included genetic influences (as inherited from birth mothers), prenatal risk, and growth in child negative emotionality. Structural equation modeling indicated that the effect of prenatal risk on toddler effortful attention at age 27 months became nonsignificant once genetic influences were considered in the model. In addition, genetic influences had unique effects on toddler effortful attention. Latent growth modeling indicated that increases in toddler negative emotionality from 9 to 27 months were associated with poorer delay of gratification and poorer language development. Similar results were obtained in models incorporating birth father data. Mechanisms of intergenerational transmission of EF deficits are discussed.

Stress system development from age 4.5 to 6: Family environment predictors and adjustment implications of HPA activity stability versus change

This study addressed early calibration of stress systems by testing links between adversity exposures, developmental stability of hypothalamic-pituitary-adrenal (HPA) axis activity, and behavior problems in a sample of adopted children. Families (n=200) were assessed when the child was 9, 18, and 27 months, 4.5 and 6 years to collect adversity information-parent psychopathology, stress, financial need, and home chaos. Morning and evening cortisol samples at the final two assessments indexed child HPA activity, and parent-reported internalizing and externalizing at the final assessment represented child behavior outcomes. Increases in cumulative adversity from 4.5 to 6 related to higher child morning cortisol, whereas age six cumulative adversities related to lower, unstable child evening cortisol. Examination of specific adversity dimensions revealed associations between (1) increasing home chaos and stable morning cortisol, which in turn related to internalizing problems; and (2) high parental stress and psychopathology and lower, unstable evening cortisol, which in turn related to externalizing problems.

Raised by depressed parents: is it an environmental risk?

Abstract The mechanisms explaining how parental depression compromises healthy child development are complex and multifaceted, with genetic and environmental pathways intertwined. Reexamination of whether and how maternal and paternal depression serve as environmental risk factors is important because such an investigation can be helpful to identify modifiable mechanisms that are accessible to interventions. We review studies that have employed designs that isolate the effects of the environment from genetic influences, including adoption studies and children of twins studies. Findings indicate that maternal depression is an environmental risk factor for the emotional, behavioral, and neurobiological development of children. Although more studies are needed, preliminary findings suggest that paternal depression appears to be a weaker environmental risk as compared to maternal depression, at least during infancy and toddlerhood. Implications for theory and future research are discussed.

The relationship between parental depressive symptoms and offspring psychopathology: Evidence from a children-of-twins study and an adoption study

Background Parental depressive symptoms are associated with emotional and behavioural problems in offspring. However, genetically informative studies are needed to distinguish potential causal effects from genetic confounds, and longitudinal studies are required to distinguish parent-to-child effects from child-to-parent effects. Method We conducted cross-sectional analyses on a sample of Swedish twins and their adolescent offspring (n = 876 twin families), and longitudinal analyses on a US sample of children adopted at birth, their adoptive parents, and their birth mothers (n = 361 adoptive families). Depressive symptoms were measured in parents, and externalizing and internalizing problems measured in offspring. Structural equation models were fitted to the data. Results Results of model fitting suggest that associations between parental depressive symptoms and offspring internalizing and externalizing problems remain after accounting for genes shared between parent and child. Genetic transmission was not evident in the twin study but was evident in the adoption study. In the longitudinal adoption study child-to-parent effects were evident. Conclusions We interpret the results as demonstrating that associations between parental depressive symptoms and offspring emotional and behavioural problems are not solely attributable to shared genes, and that bidirectional effects may be present in intergenerational associations.

Toward an Understanding of the Role of the Environment in the Development of Early Callous Behavior.

Key to understanding the long-term impact of social inequalities is identifying early behaviors that may signal higher risk for later poor psychosocial outcomes, such as psychopathology. A set of early-emerging characteristics that may signal risk for later externalizing psychopathology is callous-unemotional (CU) behavior. CU behavior predicts severe and chronic trajectories of externalizing behaviors in youth. However, much research on CU behavior has focused on late childhood and adolescence, with little attention paid to early childhood when preventative interventions may be most effective. In this article, we summarize our recent work showing that (a) CU behavior can be identified in early childhood using items from common behavior checklists, (b) CU behavior predicts worse outcomes across early childhood, (c) CU behavior exhibits a nomological network distinct from other early externalizing behaviors, and (d) malleable environmental factors, particularly parenting, may play a role in the development of early CU behaviors. We discuss the challenges of studying contextual contributors to the development of CU behavior in terms of gene-environment correlations and present initial results from work examining CU behavior in an adoption study in which gene-environment correlations are examined in early childhood. We find that parenting is a predictor of early CU behavior even in a sample in which parents are not genetically related to the children.

Examining the developmental history of child maltreatment, peer relations, and externalizing problems among adolescents with symptoms of paranoid personality disorder

This study examined the childhood history of maltreatment, peer relations, and externalizing problems among individuals who manifested low, moderate, or high symptom levels of paranoid personality disorder (PPD) in adolescence. Participants included 174 children who attended a longitudinal summer camp research program between the ages of 9 to 12. Multiple sources of information (self-, peer, and counselor reports) were utilized. Subsequently, they participated in a personality disorder assessment during adolescence (mean age = 15.30). The results indicated that children who manifested higher levels of PPD symptoms in adolescence had higher odds of having a history of child maltreatment. Children who manifested high levels of PPD symptoms in adolescence showed a faster growth rate for peer bullying and externalizing problems in childhood. In addition, their peers rated them as less cooperative, less likely to be leaders, and more likely to initiate fights. These findings suggested that children who manifested elevated PPD symptoms in adolescence had shown early signs of behavioral disturbances in childhood, some of which gradually worsened as they approach adolescence.

Adoptive Parent Hostility and Children's Peer Behavior Problems: Examining the Role of Genetically-Informed Child Attributes on Adoptive Parent Behavior

Socially disruptive behavior during peer interactions in early childhood is detrimental to childrens social, emotional, and academic development. Few studies have investigated the developmental underpinnings of childrens socially disruptive behavior using genetically sensitive research designs that allow examination of parent-on-child and child-on-parent (evocative genotype-environment correlation [rGE]) effects when examining family process and child outcome associations. Using an adoption-at-birth design, the present study controlled for passive genotype-environment correlation and directly examined evocative rGE while examining the associations between family processes and childrens peer behavior. Specifically, the present study examined the evocative effect of genetic influences underlying toddler low social motivation on mother-child and father-child hostility and the subsequent influence of parent hostility on disruptive peer behavior during the preschool period. Participants were 316 linked triads of birth mothers, adoptive parents, and adopted children. Path analysis showed that birth mother low behavioral motivation predicted toddler low social motivation, which predicted both adoptive mother-child and father-child hostility, suggesting the presence of an evocative genotype-environment association. In addition, both mother-child and father-child hostility predicted childrens later disruptive peer behavior. Results highlight the importance of considering genetically influenced child attributes on parental hostility that in turn links to later child social behavior. Implications for intervention programs focusing on early family processes and the precursors of disrupted child social development are discussed.