Transactional relations between early child temperament, structured parenting, and child outcomes: A three-wave longitudinal study.

While child self-regulation is shaped by the environment (e.g., the parents' caregiving behaviors), children also play an active role in influencing the care they receive, indicating that children's individual differences should be integrated in models relating early care to children's development. We assessed 409 children's observed temperamental behavioral inhibition (BI), effortful control (EC), and the primary caregiver's parenting at child ages 3 and 5. Parents reported on child behavior problems at child ages 3, 5, and 8. Mediation analyses were conducted to examine relations between child temperament and parenting in predicting child problems. BI at age 3 was positively associated with structured parenting at age 5, which was negatively related to child internalizing and attention-academic problems at age 8. In contrast, parenting at child age 3 did not predict child BI or EC at age 5, nor did age 3 EC predict parenting at age 5. Findings indicate that child behavior may shape the development of caregiving and, in turn, long-term child adjustment, suggesting that studies of caregiving and child outcomes should consider the role of child temperament toward developing more informative models of child-environment interplay.

Child sex moderates the relationship between cortisol stress reactivity and symptoms over time.

BACKGROUND: Past work suggests that individual differences in stress reactivity have implications for the development of psychopathology; in particular, females' stress reactivity appears more closely tied to internalizing symptoms than males' reactivity. Conversely, males who are under-reactive to threat may be at risk for externalizing problems. However, little is known about when such differences may emerge, although this knowledge could have implications for early prevention. METHODS: Cortisol reactivity to a laboratory stressor was assessed in 409 three-year-old children (201 boys), along with parent-reported children's internalizing (anxiety and depression) and externalizing (oppositional-defiant and attention problems and hyperactivity) symptoms. Parent-reported symptoms were re-collected at child ages 5 (N = 379) and 8 (N = 364). Multilevel modelling was used to investigate whether the relationship between cortisol reactivity and symptoms differed between boys and girls over time. RESULTS: Girls with lower cortisol reactivity showed a negative association between depressive symptoms and time, while girls with higher reactivity showed no such association. No interaction between sex and cortisol reactivity was found for anxious symptoms. Boys with higher cortisol reactivity showed a negative association between symptoms and time, while boys with lower cortisol reactivity showed no such association. Time and ADHD symptoms were unrelated for boys, regardless of their cortisol reactivity. CONCLUSIONS: Findings suggest that the implications of stress reactivity indexed via cortisol vary for boys and girls, as well as for different symptom manifestations.

The serotonin transporter promoter polymorphism moderates the continuity of behavioral inhibition in early childhood.

Persistently elevated behavioral inhibition (BI) in children is a marker of vulnerability to psychopathology. However, little research has considered the joint influences of caregiver and child factors that may moderate the continuity of BI in early childhood, particularly genetic variants that may serve as markers of biological plasticity, such as the serotonin transporter linked polymorphic region (5-HTTLPR). We explored this issue in 371 preschoolers and their caregivers, examining whether parent characteristics (i.e., overinvolvement or anxiety disorder) and child 5-HTTLPR influenced the continuity of BI between ages 3 and 5. Measures were observational ratings of child BI, observational and questionnaire measures of parenting, and parent interviews for anxiety disorder history, and children were genotyped for the 5-HTTLPR. Parent factors did not moderate the association between age 3 and age 5 BI; however, child BI at age 3 interacted with children's 5-HTTLPR variants to predict age 5 BI, such that children with at least one copy of the short allele exhibited less continuity of BI over time relative to children without this putative plasticity variant. Findings are consistent with previous work indicating the 5-HTTLPR short variant increases plasticity to contextual influences, thereby serving to decrease the continuity of BI in early childhood.

Hair cortisol concentrations in higher- and lower-stress mother-daughter dyads: A pilot study of associations and moderators.

Hair cortisol concentrations (HCC) are receiving increased attention as a novel biomarker of psychophysiological responses to chronic stress, with potential relevance for psychopathology risk research. We examined the validity of HCC as a marker of psychosocial stress in mother (M(age) = 37.87 years)-daughter (M(age) = 7.62 years) dyads characterized by higher (n = 30) or lower (n = 30) maternal chronic stress. Additionally, we examined whether early care moderated similarity of HCC levels within dyads. Higher-stress mothers had significantly lower HCC compared to lower-stress mothers, consistent with other research showing that chronic stress leads to blunted HPA axis activity over time. Further, HCC in daughters were significantly and positively associated with previously assessed salivary cortisol stress reactivity. Finally, mother-daughter HCC associations were significantly moderated by negative parenting styles, such that associations became stronger as quality of parenting decreased. Findings overall indicate that HCC may be a useful marker of cortisol responses to chronic stress.

The role of parenting and dopamine D4 receptor gene polymorphisms in children's inhibitory control.

Temperamental effortful control has important implications for children's development. Although genetic factors and parenting may influence effortful control, few studies have examined interplay between the two in predicting its development. The current study investigated associations between parenting and a facet of children's effortful control, inhibitory control (IC), and whether these associations were moderated by whether children had a 7-repeat variant of the DRD4 exon III VNTR. A community sample of 409 3-year-olds completed behavioural tasks to assess IC, and observational measures of parenting were also collected. Negative parenting was associated with lower child IC. The association between children's IC and positive parenting was moderated by children's DRD4 7-repeat status, such that children with at least one 7-repeat allele displayed lower IC than children without this allele when positive parenting was lower. These effects appeared to be primarily influenced by parent support and engagement. Results extend recent findings suggesting that some genetic polymorphisms may increase vulnerability to contextual influences.

Effortful control and parenting: associations with HPA axis reactivity in early childhood.

While activation of the hypothalamic-pituitary-adrenal (HPA) axis is an adaptive response to stress, excessive HPA axis reactivity may be an important marker of childhood vulnerability to psychopathology. Parenting, including parent affect during parent-child interactions, may play an important role in shaping the developing HPA system; however, the association of parent affect may be moderated by child factors, especially children's emerging self-regulatory skills. We therefore tested the relationship between parent affectivity and 160 preschoolers' cortisol reactivity during a laboratory visit, examining children's effortful control (EC) as a moderator. Greater parent negative affectivity was related to greater initial and increasing cortisol over time, but only when children were low in EC. Higher parent positive affectivity was related to a higher baseline cortisol for children with low EC and lower baseline cortisol for children with high EC. Results indicate that children's EC moderates the extent to which parent affect shapes stress reactive systems in early childhood.

Catechol-O-methyltransferase gene val158met polymorphism and depressive symptoms during early childhood.

Catechol-O-Methyltransferase (COMT) is a critical regulator of catecholamine levels in the brain. A functional polymorphism of the COMT gene, val158met, has been linked to internalizing symptoms (i.e., depression and anxiety) in adolescents and adults. We extended this research by investigating whether the val158met polymorphism was associated with childhood symptoms of depression and anxiety in two independent samples of young children (Ns = 476 and 409). In both samples, preschool-aged children were genotyped for the COMT val158met polymorphism. Symptoms of psychopathology were assessed via parent interviews and primary caregiver reports. In both samples, children homozygous for the val allele had higher levels of depressive symptoms compared to children with at least one copy of the met allele. Our findings extend previous research in older participants by showing links between the COMT val158met polymorphism and internalizing symptoms in early childhood.

Parenting differentially influences the development of boys' and girls' inhibitory control.

Effortful control (EC) has important implications for children's development. While both child sex and parenting are related to child EC, and while a literature shows early sex differences in children's responses to care, interactions between care and child sex in predicting EC are not well understood. We therefore examined associations between child sex and early caregiving as predictors of children's development of a specific aspect of EC, inhibitory control (IC). A community sample of 406 three-year-old children and their caregivers completed behavioural tasks and observational measures of parenting and IC, and children were re-assessed for IC at age 5. Results showed that early care influenced change in IC over time, although caregiving was a more important influence on boys' IC than girls; specifically, differences in boys' and girls' IC at age 5 were modest when parenting was positive. The implications of a better understanding of sex differences in associations between parenting and the development of IC in early childhood are discussed. Statement of contribution What is already known on this subject? While sex differences in reactivity to early care in the development of externalizing symptoms have been explored, very little is known about such differences in children's early-emerging effortful control. What does this study add? Using a longitudinal design and independent, laboratory methods of assessing study constructs, we provide new information showing that early care appears to differentially influence boys' development of inhibitory control, a key aspect of effortful control, in early childhood.

Associations between observed temperament in preschoolers and parent psychopathology.

Parent history of psychopathology is an established marker of children's own risk for later disorder and can therefore be used as a means of validating other risks, such as child temperament. While associations between children's temperament and parent psychopathology have been reported, few studies have used observational measures of child temperament or examined trait interactions, particularly between children's affective and regulatory traits such as effortful control (EC). In this bottom-up family study of 968 three-year-olds and their parents, we examined interactions between preschoolers' observed positive and negative affectivity (NA) and EC as predictors of a known marker of psychopathology risk: parent history of disorder. Children with lower positive affectivity had an increased probability of paternal depression history in the context of higher child NA. In addition, children with lower EC and higher NA had an increased probability of maternal anxiety. Findings shed new light on the main effects and interactions that account for associations between child temperament and parent history of disorder, one of the best-established markers of an individual's own risk for future disorder, implicating reactive and regulatory traits that merit special consideration in future longitudinal work. Copyright © 2017 John Wiley & Sons, Ltd.

Catechol-O-Methyltransferase gene (val158met) polymorphisms and anxious symptoms in early childhood: The roles of hypothalamus-pituitary-adrenal axis reactivity and life stress.

Individual differences in hypothalamus-pituitary-adrenal (HPA) axis reactivity to stress (measured via salivary cortisol) have been widely implicated in the etiology of internalizing problems such as depression and anxiety. Literature suggests that stress during early childhood is an important source of contextual risk although its effects may be moderated by polymorphisms of neurotransmitter genes. The COMT val158met is one such polymorphism, and literature documents its link to internalizing problems. To extend these findings, and to better understand the role of this polymorphism in developmental risk, we investigated links between the val158met polymorphism and early-age cortisol response. Additionally, we investigated whether cortisol reactivity mediated the link between COMT and emerging internalizing symptoms. The study was conducted in a community sample of 409 preschoolers. Saliva samples were collected pre-stress task (baseline) and every 10min post-stress task for one-hour to asses cortisol response. Child anxious and depressive symptoms were tabulated based on parent-reports. Markers of early childhood stress included marital discord, socio-economic status and the UCLA Life Stress Interview. Findings indicated that the val158met polymorphism is associated with childhood cortisol response (p<0.05). A gene-environment interaction between val158met and life stress also predicted child anxiety symptoms (p<0.01). Finally, cortisol response mediated the main-effect of val158met on child anxiety symptoms (pathway ps<0.05). Analyses suggest that COMT val158met moderates the influence of early life stress on preschool-age symptoms of anxiety. Additionally, cortisol reactivity acts as a mechanistic mediator of the main-effect of COMT genotype on child anxious symptoms.

Gene-environment correlations in the cross-generational transmission of parenting: Grandparenting moderates the effect of child 5-HTTLPR genotype on mothers' parenting.

Evidence suggests that parenting is associated cross-generationally and that children's genes may elicit specific parenting styles (evocative gene-environment correlation). This study examined whether the effect of children's genotype, specifically 5-HTTLPR, on mothers' parenting behaviors was moderated by her own parenting experiences from her mother. Two independent samples of three-year-olds (N = 476 and 405) were genotyped for the serotonin transporter gene, and observational measures of parenting were collected. Mothers completed measures of the parenting they received as children. The child having a short allele on 5-HTTLPR was associated with more maternal hostility (sample 1 and 2) and with less maternal support (sample 1), but only if the mother reported lower quality grandmothers' parenting (abuse and indifference in Sample 1 and lower levels of grandmother care in Sample 2). Results support the possibility of a moderated evocative gene-environment correlation.

Higher- and lower-order factor analyses of the Children's Behavior Questionnaire in early and middle childhood.

The Children's Behavior Questionnaire (CBQ; Rothbart, Ahadi, & Hershey, 1994), a 195-item parent-report questionnaire, is one of the most widely used measures of child temperament, with previous analyses of its scales suggesting that 3 broad factors account for the overarching structure of child temperament (Rothbart, Ahadi, Hershey, & Fisher, 2001). However, there are no published item-level factor analyses of the CBQ, meaning that it is currently unclear whether items clearly load onto CBQ scales as proposed by its developers. Additionally, although the CBQ is intended to cover a broad window of development (i.e., ages 3-7), little is known about whether the structure of the CBQ differs depending on child age. The present study used a bottom-up approach to examine the lower- and higher-order structure of the CBQ in a large community sample of children at ages 3 (N = 944) and 5/6 (N = 853). Item-level exploratory factor analyses (EFAs) identified 88 items at age 3 and 87 items at age 5/6 suitable (i.e., with loadings ≥.40) for constructing lower-order factors. Of the lower-order factors derived at ages 3 and 5/6, fewer than half resembled original CBQ scales (Rothbart et al., 1994, 2001). Higher-order EFAs of the lower-order factors suggested that a 4-factor structure was the best fit at both ages 3 and 5/6. Thus, results indicate that a substantial number of CBQ items do not load well on a lower-order factor and that more than 3 factors are needed to account for its higher-order structure.

Links between white matter microstructure and cortisol reactivity to stress in early childhood: evidence for moderation by parenting.

Activity of the hypothalamic-pituitary-adrenal axis (measured via cortisol reactivity) may be a biological marker of risk for depression and anxiety, possibly even early in development. However, the structural neural correlates of early cortisol reactivity are not well known, although these would potentially inform broader models of mechanisms of risk, especially if the early environment further shapes these relationships. Therefore, we examined links between white matter architecture and young girls' cortisol reactivity and whether early caregiving moderated these links. We recruited 45 6-year-old girls based on whether they had previously shown high or low cortisol reactivity to a stress task at age 3. White matter integrity was assessed by calculating fractional anisotropy (FA) of diffusion-weighted magnetic resonance imaging scans. Parenting styles were measured via a standardized parent-child interaction task. Significant associations were found between FA in white matter regions adjacent to the left thalamus, the right anterior cingulate cortex, and the right superior frontal gyrus (all ps < .001). Further, positive early caregiving moderated the effect of high cortisol reactivity on white matter FA (all ps ≤ .05), with high stress reactive girls who received greater parent positive affect showing white matter structure more similar to that of low stress reactive girls. Results show associations between white matter integrity of various limbic regions of the brain and early cortisol reactivity to stress and provide preliminary support for the notion that parenting may moderate associations.

Child temperament and parental depression predict cortisol reactivity to stress in middle childhood.

Children's cortisol reactivity to stress is an important mediator of depression risk, making the search for predictors of such reactivity an important goal for psychopathologists. Multiple studies have linked maternal depression and childhood behavioral inhibition (BI) independently to child cortisol reactivity, yet few have tested multivariate models of these risks. Further, paternal depression and other child temperament traits, such as positive emotionality (PE), have been largely ignored despite their potential relevance. We therefore examined longitudinal associations between child fear/BI and PE and parental depression, and children's cortisol stress reactivity, in 205 7-year-olds. Paternal depression and child fear/BI predicted greater cortisol stress reactivity at a follow-up of 164 9-year-olds, and maternal depression and child PE interacted to predict children's cortisol reactivity, such that higher child PE predicted lower cortisol reactivity in the context of maternal depression. Results highlight the importance of both parents' depression, as well as multiple facets of child temperament, in developing more comprehensive models of childhood cortisol reactivity to stress.

HPA axis reactivity in early childhood: associations with symptoms and moderation by sex.

Sex differences in rates of internalizing disorders have been attributed in part to heightened sensitivity to stress in females. While the sex difference in disorder rates becomes most pronounced in adolescence, developmental research suggests that stress reactivity in girls may be related to elevated internalizing symptoms even in childhood. We therefore examined whether child sex moderated associations between symptoms of psychopathology and cortisol reactivity to a standardized stress task in 409 three-year-old community-dwelling children. Anxious symptoms were associated with elevated cortisol reactivity, but only in girls. Externalizing symptoms were unrelated to baseline cortisol or cortisol reactivity, and no evidence for moderation by child sex was found. Results suggest that cortisol reactivity to stress in early childhood has a sex-specific association with girls' internalizing symptoms.

Assessing stress reactivity indexed via salivary cortisol in preschool-aged children.

Identifying a stressor paradigm that elicits mean increases in salivary cortisol in young children has proven elusive, possibly due to characteristics of the paradigms used and how and when cortisol is sampled. We therefore examined the validity of a standardized task (adapted from Lewis and Ramsay, 2002) and procedures developed to assess cortisol reactivity in 215 preschool-aged children. Children participated in a standardized stress task during a home visit, which was videorecorded for future coding. Salivary cortisol samples were obtained at baseline and 10, 20, 30, 40, and 50 min post-stress. In support of the validity of the task, significant increases in cortisol levels from baseline were found, followed by a significant decline, and a quadratic function provided a good fit to the data. Children also showed a significant increase in negative emotions and a decrease in positive emotions over the course of the stress task. Results indicate that the task successfully elicited the hypothesized cortisol response in 3-year-old children.

Genotyping the BDNF rs6265 (val66met) polymorphism by one-step amplified refractory mutation system PCR.

BACKGROUND: The brain derived neutrophic factor (BDNF), a 27 kD polypeptide, is one of the most widely expressed neurotrophins in the brain, regulating neural development and plasticity. The BDNF gene contains a functional single-nucleotide polymorphism (rs6265), which results in a valine to methionine substitution (val66met), leading to reduced mature BDNF expression. This polymorphism has been widely implicated in a host of psychiatric disorders and is a focus of many ongoing psychiatric genetic studies. OBJECTIVE: To develop an efficient and rapid method to detect the val66met polymorphism in a one-step PCR reaction. METHOD AND RESULTS: We have designed four PCR primers that amplify the BDNF gene region containing rs6265. The specificity of the four primers in a single PCR reaction amplifies two allele-specific amplicons (253 and 201 bp) and the entire region (401 bp) as an internal control, which are easily distinguished on a polyacrylamide gel. The effectiveness and efficiency of the results are validated by traditional NlaIII restriction enzyme digestion, sequencing of resulting bands and confirmation on 308 genomic DNA samples. CONCLUSION: This new method describes a rapid, sensitive, cost effective and high throughput genotyping of the BDNF val66met polymorphism, ideal for large-scale genotyping studies.